<PAGE>   1
                UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             Washington, D. C. 20549

                                    FORM 10-Q

     [X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934

                  For the quarterly period ended JUNE 30, 1999


                       Commission File Number : 001-14575


                          VISTA ENERGY RESOURCES, INC.
                          ----------------------------
             (Exact name of registrant as specified in its charter)


              Delaware                                  75-2766114
              --------                                  ----------
  (State or other jurisdiction of                    (I.R.S. Employer
   incorporation or organization)                   Identification No.)

       550 West Texas Avenue, Suite 700, Midland, Texas         79701
       ------------------------------------------------         -----
           (Address of principal executive offices)           (Zip Code)

                                 (915) 570-5045
                                 --------------
              (Registrant's telephone number, including area code)

                                      NONE
                                      ----
              (Former name, former address and former fiscal year,
                         if changed since last report)


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Act of 1934 during the
preceding 12 months (or for such shorter period that the registrant was required
to file such reports) and (2) has been subject to such filing requirements for
the past 90 days.
Yes X  No
   ----  ----

Indicate the number of shares outstanding of each of the issuers classes of
common stock, as of the latest practicable date:

          Class                              Outstanding as of  August 1,  1999
Common stock, $.01 par value                              16,312,336

<PAGE>   2

                          VISTA ENERGY RESOURCES, INC.
             FORM 10-Q FOR THE QUARTERLY PERIOD ENDED JUNE 30, 1999



                                      INDEX



PART I.  FINANCIAL INFORMATION
<TABLE>
                                                                           Page
<S>      <C>                                                               <C>
Item 1.  Financial Statements

         Consolidated Balance Sheets
         at June 30, 1999 (Unaudited) and December 31, 1998 (Audited)         3

         Unaudited Consolidated Statement of Operations
         for the Three and Six Months Ended June 30, 1999 and 1998            4

         Unaudited Consolidated Statement of Cash Flows
         for the Six Months Ended June 30, 1999 and 1998                      5

         Notes to Unaudited Consolidated Financial Statements                 6

Item 2.  Management's Discussion and Analysis of Financial Condition
         and Results of Operations                                           13

PART II. OTHER INFORMATION                                                   21

Item 1.  Legal Proceedings

Item 2.  Changes in Securities

Item 3.  Defaults Upon Senior Securities

Item 4.  Submission of Matters to a Vote of Security Holders

Item 5.  Other Information

Item 6.  Exhibits and Reports on Form 8-K

         Signatures
</TABLE>


                                       2
<PAGE>   3
                         PART I - FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

                          VISTA ENERGY RESOURCES, INC.
                           CONSOLIDATED BALANCE SHEETS

<TABLE>
<CAPTION>
                              ASSETS                                              JUNE 30,        DECEMBER 31,
                                                                                    1999              1998
                                                                                ------------      ------------
                                                                                (UNAUDITED)         (AUDITED)
<S>                                                                             <C>               <C>
CURRENT ASSETS:
  Cash and cash equivalents                                                     $    802,490      $
  Accounts receivable:
     Oil and gas sales                                                             2,951,005         1,498,727
     Trade                                                                           508,813           900,401
  Other                                                                              249,458           262,218
                                                                                ------------      ------------
         Total current assets                                                      4,511,766         2,661,346
PROPERTY AND EQUIPMENT:
  Oil and gas properties, based on successful efforts accounting                  90,057,670        86,970,665
  Other                                                                              562,896           529,771
                                                                                ------------      ------------
                                                                                  90,620,566        87,500,436
  Less accumulated depreciation, depletion and amortization                      (33,168,811)      (30,956,448)
                                                                                ------------      ------------
   Property and equipment, net                                                    57,451,755        56,543,988
OTHER ASSETS, NET                                                                    804,123           537,983
                                                                                ------------      ------------
         Total Assets                                                           $ 62,767,644      $ 59,743,317
                                                                                ============      ============
                      LIABILITIES AND STOCKHOLDERS' EQUITY
CURRENT LIABILITIES:
  Accounts payable                                                                 3,265,378         2,829,495
  Accrued expenses                                                                   479,526           259,117
                                                                                ------------      ------------
         Total current liabilities                                                 3,744,904         3,088,612
LONG-TERM DEBT                                                                    52,640,621        50,730,894
DEFERRED TAX LIABILITY                                                               510,408           350,000
OTHER LONG-TERM LIABILITIES                                                          205,116           205,116
STOCKHOLDERS' EQUITY:
      Common Stock, par value $.01 per share;
      Authorized - 50,000,000 shares; issued 16,373,628 at June
        30, 1999 and December 31, 1998, respectively;                                163,736           163,736
       Treasury Stock -- 61,292 shares                                              (212,070)         (212,070)
      Additional paid in capital                                                  25,071,099        25,071,099
      Retained earnings (deficit)                                                (19,356,170)      (19,654,070)
      Partners' equity                                                                    --                --
                                                                                ------------      ------------
         Total stockholders' equity                                                5,666,595         5,368,695
                                                                                ------------      ------------
         Total liabilities and stockholders' equity                             $ 62,767,644      $ 59,743,317
                                                                                ============      ============
</TABLE>

The accompanying notes are an integral part of these consolidated financial
statements.


                                       3
<PAGE>   4

                          VISTA ENERGY RESOURCES, INC.
                      CONSOLIDATED STATEMENTS OF OPERATIONS

<TABLE>
<CAPTION>
                                                             Three Months Ended                  Six Months Ended
                                                                  June 30,                           June 30,

                                                          1999                1998             1999             1998
                                                       ------------       -----------      ------------      ------------
                                                       (UNAUDITED)        (UNAUDITED)      (UNAUDITED)       (UNAUDITED)
<S>                                                    <C>                <C>              <C>               <C>
REVENUES:
   Oil and gas sales                                   $  4,756,810       $2 ,003,111      $  8,485,051      $  4,057,279
                                                       ------------       -----------      ------------      ------------
       Total revenues                                     4,756,810         2,003,111         8,485,051         4,057,279
COSTS AND EXPENSES:
       Lease Operating                                    1,659,895           952,802         2,859,738         1,939,530
       Exploration Costs                                     27,563                --            38,768                --
       Depreciation, depletion and amortization           1,041,825           467,068         2,212,363           962,026
       General and administrative                           583,390           312,710           968,136           620,665
       Amortization of Unit Option Awards                        --            25,328                --           192,177
                                                       ------------       -----------      ------------      ------------
            Total costs and expenses                      3,312,673         1,757,908         6,079,005         3,714,398
                                                       ------------       -----------      ------------      ------------
            Operating income (loss)                       1,444,137           245,203         2,406,046           342,881
       Gain (loss) on sale of property                       53,227          (192,898)           70,029          (192,898)
       Interest income                                        3,156                --             4,978                --
       Interest expense                                  (1,066,714)         (370,509)       (2,035,359)         (713,961)
       Other (expense)/income, net                            8,510            16,170            12,614            40,291
                                                       ------------       -----------      ------------      ------------
NET INCOME (LOSS) BEFORE TAXES                              442,316          (302,034)          458,308          (523,687)
         Income tax expense (benefit):
           Current                                               --                --                --                --
           Deferred                                         154,811                --           160,408                --
           Pro Forma benefit (provision) for taxes               --           105,712                --           183,290
                                                       ------------       -----------      ------------      ------------
NET INCOME (LOSS)                                      $    287,505       $  (196,322)     $    297,900      $   (340,397)
                                                       ============       ===========      ============      ============
Earnings (loss) per share:
       Basic                                           $        .02       $      (.02)     $        .02      $       (.03)
                                                       ============       ===========      ============      ============
       Diluted                                         $        .01       $      (.02)     $        .01      $       (.03)
                                                       ============       ===========      ============      ============
Weighted Average Shares Outstanding (Note 6)             28,393,409        11,903,506        28,393,409        11,903,506
                                                       ============       ===========      ============      ============

             The accompanying notes are an integral part of these consolidated financial statements.
</TABLE>


                                       4
<PAGE>   5
                          VISTA ENERGY RESOURCES, INC.
                      CONSOLIDATED STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                                          Six Months Ended
                                                                              June 30,
                                                                        1999              1998
                                                                     -----------      ------------
                                                                     (UNAUDITED)       (UNAUDITED)
<S>                                                                  <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
  Net income (loss)  before pro forma tax expense .................. $   297,900      $  (523,687)
  Adjustments to reconcile net income (loss)
    before taxes to cash provided by
    operating activities:
    Depreciation, depletion and amortization .......................   2,212,363          962,026
    Amortization of deferred borrowing cost ........................      56,281               --
    Provision for income tax .......................................     160,408               --
    Amortization of unit option awards .............................          --          192,177
    (Gain) Loss  on sale of property ...............................     (70,029)         192,959
  Changes in working capital
    Decrease (increase) in accounts receivable .....................  (1,060,690)         (21,897)
    Decrease (increase) in other current assets ....................      12,760           39,198
    Increase in other non-current assets ...........................    (322,421)              --
    Decrease (increase) in accounts payable and accrued expenses ...     656,292         (214,800)
                                                                     -----------      ------------
    Net cash provided by (used in) operating activities ............   1,942,864          625,976
                                                                     -----------      ------------
CASH FLOWS FROM INVESTING ACTIVITIES:
  Additions to property and equipment ..............................  (3,298,333)      (1,717,694)
  Proceeds from sales of property and Equipment ....................     248,231          131,864
                                                                     -----------      ------------
     Net cash used in investing activities .........................  (3,050,102)      (1,585,830)
                                                                     -----------      ------------
CASH FLOWS FROM FINANCING ACTIVITIES:

  Payment of borrowings ........................................      (1,010,273)              --
  Proceeds from issuance of debt ...............................       2,920,000          500,000
                                                                     -----------      ------------
         Net cash provided by financing activities .............       1,909,727          500,000
                                                                     -----------      ------------
NET INCREASE (DECREASE) IN CASH AND CASH
    EQUIVALENTS ................................................         802,489         (459,854)

CASH AND CASH EQUIVALENTS:
  Beginning of period ..........................................              --          527,129
                                                                     -----------      ------------
  End of period ................................................     $   802,489      $    67,275
                                                                     ===========      ============

           The accompanying notes are an integral part of these consolidated financial statements.
</TABLE>


                                       5
<PAGE>   6

                          VISTA ENERGY RESOURCES, INC.
              NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS
                                  JUNE 30, 1999
                                   (UNAUDITED)

1. ORGANIZATION:

Organization

         Vista Energy Resources, Inc. and its subsidiaries (collectively,
"Vista" or the "Company") is a Delaware corporation whose common stock is listed
and traded on the American Stock Exchange. The Company was incorporated in May
1998 for the purpose of continuing and consolidating the operations of Vista
Resources Partners, L.P., a Texas limited partnership (the "Vista Partnership"),
and Midland Resources, Inc., a publicly traded Texas corporation ("Midland
Resources"). The merger of the Vista Partnership and Midland Resources (the
"Midland Merger") was completed on October 28, 1998. The Company is an
independent oil and gas company engaged in the acquisition, exploration,
production and development of oil and natural gas primarily in the Permian Basin
of West Texas and Southeastern New Mexico and the onshore Gulf Coast region of
South Texas.

         Vista Resources I, Inc., a Texas corporation (the "General Partner"),
now a wholly-owned subsidiary of the Company, serves as the sole general partner
of the Vista Partnership. Vista Resources, Inc., a wholly owned subsidiary of
the Company ("Vista Resources"), currently serves as the operator of properties
in which the Company or its subsidiaries acquires or otherwise owns operating
working interests.

         On October 28, 1998, pursuant to the terms of an Exchange Agreement
dated June 15, 1998 (the "Exchange Agreement"), the Company acquired all of the
outstanding partnership interests of the Vista Partnership and all of the
outstanding shares of common stock of the General Partner in exchange for shares
of Common Stock of the Company (the "Conversion"). The Conversion was accounted
for as a transfer of assets and liabilities between affiliates under common
control and resulted in no change in carrying values of these assets and
liabilities. The Conversion and other transactions contemplated by the Exchange
Agreement were consummated immediately prior to the closing of the Midland
Merger. As a result of the Conversion and the Midland Merger, security holders
of Midland Resources acquired 4,470,123 shares or 27.3 percent of the
outstanding "Common Stock" of the Company, and security holders of the Vista
Partnership acquired 11,903,506 shares of Common Stock, or 72.7 percent.
Accordingly, the accompanying financial statements include the results of
operations of the Company and Midland Resources since October 28, 1998, and the
results of the Vista Partnership prior to that date.



                                       6
<PAGE>   7

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

Basis of Presentation

         In management's opinion, the accompanying consolidated financial
statements contain all adjustments necessary to present fairly the financial
position as of June 30, 1999 and related results of operations and cash flows
for the three and six months ended June 30, 1999 and 1998 of the Company and its
wholly-owned subsidiaries. All significant intercompany transactions and
balances have been eliminated in preparation of the consolidated financial
statements.

         The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities at the date of the financial
statements and the reported amounts of revenues and expenses during the
reporting period. Actual results could differ from those estimates.

         Certain information and footnote disclosures normally included in
financial statements prepared in accordance with generally accepted accounting
principles have been condensed or omitted in this Form 10-Q pursuant to the
rules and regulations of the Securities and Exchange Commission. These
consolidated financial statements should be read in conjunction with the audited
financial statements and notes thereto included in the Company's 1998 Form 10-K.

3. SIGNIFICANT ACQUISITIONS OF OIL AND GAS PROPERTIES AND OTHER ASSETS:

1999 Acquisitions

         The Company made no material acquisitions during the first six months
of 1999.

1998 Acquisitions

         On October 28, 1998, the Company completed the Conversion and the
Midland Merger (see Note 1). The Company issued 4,470,123 shares of common stock
and 995,375 warrants with an exercise price of $4.00 to the Midland Resources
shareholders and warrant holders and assumed 261,800 Midland Resources employee
options (which expired without exercise in February 1999). The Company also
assumed 2,522,670 Midland Resources warrants to effect the Midland Merger. In
connection with the Midland Merger, the Company issued 11,903,506 shares of
common stock and 8,563,028 warrants with an exercise price of $4.00 to the Vista
Partnership's existing partners so that the security holders of the Vista
Partnership would own 72.7 percent of the Company's outstanding stock and
warrants. The estimated value recorded for the consideration paid to the Midland
Resources shareholders was based on the market value of the Midland Resources
securities at the announcement of the Midland Merger on May 26, 1998. The
allocation of the purchase price for the assets acquired and liabilities assumed
was as follows:



                                       7
<PAGE>   8

<TABLE>
<S>                                  <C>
         Working capital             $   (895,132)
         Oil and gas properties      $ 37,296,391
         Debt assumed                $(10,445,394)
         Deferred income taxes       $ (6,910,351)
                                     ------------

                 Purchase Price      $ 19,045,514
                                     ============
</TABLE>

         From the announcement of the Midland Merger in May 1998 to the closing
in October 1998, the trading price of the Midland Resources common stock
declined. In addition, oil prices decreased significantly from May 1998 to
December 1998. Accordingly, at December 31, 1998 the Company recorded a
significant impairment charge to the allocated value of oil and gas properties
recorded in purchase accounting for the Midland Merger. The total impairment
recognized related to the properties acquired from Midland Resources was
approximately $22.2 million.

         On December 18, 1998 (effective date of October 1, 1998), the Company
acquired working interests ranging from 65 percent to 85 percent in a group of
oil and gas producing leases from IP Petroleum Company, Inc. and certain of its
working interest partners. These leases are located primarily in the War-Wink
area of Ward and Winkler Counties, Texas, and the interests were acquired for a
purchase price of $19.1 million (the "IP Acquisition"). Collectively, the
Midland Merger and the IP Acquisition are referred to herein as the "1998
Acquisitions."

Pro Forma Condensed Statements of Operations

         The following unaudited Pro Forma Condensed Combined Statements of
Operations for the six months ended June 30, 1998 give effect to the 1998
Acquisitions as if the acquisitions had been consummated at January 1, 1998. The
unaudited pro forma data is presented for illustrative purposes only and is not
necessarily indicative of the operating results that would have occurred had the
transactions been consummated at the dates indicated, nor are they necessarily
indicative of future operating results.

            Pro Forma Condensed Consolidated Statements of Operations
                                   (unaudited)

<TABLE>
<CAPTION>
                               For the six months ended June 30,
                               ---------------------------------
                                             1998
                                       -----------------
<S>                                    <C>
Total revenues                            $ 9,410,664
Net income (loss)                             454,363
Basic Net income (loss)                           .03
Diluted Earnings per share                        .03

</TABLE>


                                       8
<PAGE>   9

4.  LONG-TERM DEBT:

         As of June 30, 1999, $52.6 million was outstanding under a $100 million
revolving Credit Agreement dated December 18, 1998, and accompanying note (the
"Credit Facility") with BankBoston subject to a borrowing base which is
redetermined on a semi-annual basis. The borrowing base at June 30, 1999, was
$55 million. The next scheduled borrowing base redetermination is scheduled for
August 31, 1999. Borrowings under the Credit Facility are to be used for the
acquisition and development of oil and gas properties and for other Company
purposes.

         The Company has two options with respect to interest rate elections on
borrowings under the Credit Facility. The Company may either elect an interest
rate equal to (i) the Alternate Base Rate plus the Applicable Margin ("Prime
Basis") or (ii) a Eurodollar rate (i.e., London Interbank Offered Rate) plus the
Applicable Margin ("LIBOR Basis"). The Applicable Margin (as defined in the
Credit Facility) will be adjusted for Borrowing Base usage. The LIBOR Basis
option provides for one-, two-, three-, six- and twelve- month interest periods.
At June 30, 1999, the effective interest rate on the amount outstanding was 7.56
percent.

         Unless otherwise extended by BankBoston, the Credit Facility converts
to a three-year fully amortizing term loan at December 15, 2001.

         The obligations of the Company under the Credit Facility are secured by
a first lien deed of trust on the Company's interests in certain of its oil and
gas properties.

         The Credit Facility contains two financial covenants including a
minimum current ratio, including available borrowings, of 1:1 and an interest
coverage to EBITDA test (2.0 to 1.0 for the four-fiscal quarter period ending
December 31, 1998; 2.25 to 1.0 for the four-fiscal quarter period ending March
31, 1999; and 2.5 to 1.0 for each four-fiscal quarter period thereafter). The
Credit Facility also includes covenants which, among other things, restrict the
incurrence of additional indebtedness and the sale or acquisition of oil and gas
properties above certain levels without the consent of the lender.

         Effective as of December 23, 1997, the Company entered into an interest
rate swap accounted for as a hedge with any realized gains or losses
appropriately recorded as interest expense (See Note 7 for further discussion of
hedge accounting.). The swap consists of a $10 million notional amount of
indebtedness at a fixed swap rate of 6.02 percent three-month LIBOR for the
Company. The term of this swap ends on December 23, 1999. Effective as of
January 1, 1999, this interest rate swap was assigned to BankBoston. In
conjunction with such assignment the terms of the swap were modified to reduce
the fixed swap rate from 6.02 percent to 5.65 percent and to extend the term of
the swap until December 23, 2000, at the option of BankBoston.



                                       9
<PAGE>   10

5. COMMITMENTS AND CONTINGENCIES:

Litigation

         At December 31, 1998, the Company was a Defendant in a lawsuit filed on
July 31, 1995, styled Manna Oil & Gas, Inc., Dobbs Oil & Gas, Inc. v. Midland
Resources, Inc. , Miresco Inc., Midland Resources Operating Company, Inc., Cause
No. 40,677. The case involved disputes with a non-operating interest owner
concerning the operation of certain Gulf Coast properties located in Copano Bay,
Aransas County, Texas, wherein the Company owns a 68 percent working interest
and is the operator of the properties. The lawsuit was settled in February 1999
by the Company acquiring all of the interests of the Plaintiffs in the subject
properties for a net purchase price of $0.7 million.

         The Company and its subsidiaries are involved in various other lawsuits
and certain governmental proceedings arising in the ordinary course of business.

6. EARNINGS PER SHARE:

         Effective December 31, 1997, the Company adopted the provisions of SFAS
128, "Earnings Per Share", which prescribes standards for computing and
presenting earnings per share ("EPS") and supersedes APB Opinion 15, "Earnings
Per Share."

         The computation of basic and diluted earnings (loss) per share were
identical for the six months ended June 30, 1999, and for the years ended
December 31, 1998 and 1997 due to the following:

         Options to purchase 261,800 shares of common stock were outstanding
         since October 28, 1998, but were not included in the computation of
         diluted EPS because the options' exercise price was greater than the
         average market price of the Common Stock. All outstanding options
         expired in February 1999.

         Warrants to purchase 12,081,073 shares of Common Stock were not
         included in the computation of EPS as they are antidilutive as a result
         of the Company's net loss for the year ended December 31, 1998.
         Warrants to purchase 12,081,073 shares of Common Stock were included in
         the computation of EPS for the period ended June 30, 1999. All of these
         warrants, 11,811,073 of which expire on November 1, 2002, with the
         remaining warrants expiring from March 1999 through June 2002, were
         still outstanding at December 31, 1998.

         As the Conversion was not completed until October 28, 1998, there were
         no potentially dilutive equity securities outstanding at either
         December 31, 1997 and 1996.


                                       10
<PAGE>   11

         EPS has been calculated for all periods presented as if the Conversion
         had been completed on January 1, 1996.



7. PRICE RISK MANAGEMENT:

Commodity Price Hedging Instruments

         The Company periodically uses derivative financial instruments to
manage crude oil and natural gas price risk. These instruments qualify as hedges
under generally accepted accounting principles and are properly recorded as
adjustments to oil and gas sales in the consolidated statements of operations.
In order to qualify for hedge accounting, each financial instrument must be
initially designated as a hedge, must appropriately reduce the price risk and
must have correlation to the commodity being hedged. If an instrument does not
qualify as a hedge, then it is accounted for as a speculative transaction, with
any unrealized gains or losses being reflected in the statement of operations.
It is the Company's policy not to engage in speculative transactions of this
nature. If a financial instrument designated as a hedge is sold, extinguished or
terminated before it matures, then the realized gain or loss is deferred and
amortized to oil and gas sales over the original life of the financial
instrument. The Company's realized gains and losses attributable to its price
risk management activities was ($0.2) million for the first six months of 1999
as compared to $.1 million for the same period in 1998.

         Set forth below is the contract amount and material terms of all crude
oil hedging instruments held by the Company at June 30, 1999 (monthly volumes
are expressed in Bbls and all prices are expressed in the calendar monthly
average of daily NYMEX closing prices for Light Sweet Crude Oil):

<TABLE>
<CAPTION>
    TRADE DATE        TYPE TRANSACTION       MONTHLY VOLUME       PUT FLOOR PRICE     CALL CEILING PRICE            TERM
    ----------        ----------------       --------------       ---------------     ------------------            ----
<S>                   <C>                    <C>                  <C>                 <C>                    <C>
     12-11-98               Swap                 40,000              $14.20 Bbl           $14.20 Bbl          8-1-99 to 6-30-00
     03-19-99               Swap                 60,000              $14.85 Bbl           $14.85 Bbl          4-1-99 to 7-31-99
     04-19-99              Collar                20,000              $15.00 Bbl           $17.00 Bbl          1-1-00 to 6-30-00
     04-19-99              Collar                40,000              $15.00 Bbl           $16.85 Bbl         7-1-00 to 12-31-00
</TABLE>

         Set forth below is the contract amount and material terms of all NYMEX
natural gas hedging instruments held by the Company at June 30, 1999 (monthly
volumes are expressed in MMBtus and prices are expressed in the monthly NYMEX
(Henry Hub) closing price for natural gas):
<TABLE>
<CAPTION>


    TRADE DATE         TYPE TRANSACTION       MONTHLY VOLUME       PUT FLOOR PRICE      CALL CEILING PRICE           TERM
    ----------         ----------------       --------------       ---------------      ------------------           ----
<S>                    <C>                    <C>                  <C>                  <C>                   <C>
     08-20-98               Collar                40,000              $2.25 Mcf             $2.42 Mcf         1-1-99 to 12-31-99
     11-12-98               Collar                50,000              $2.25 Mcf             $2.51 Mcf         1-1-99 to 12-31-99
     08-20-98               Collar                40,000              $2.17 Mcf             $2.55 Mcf         1-1-99 to 12-31-99
     12-28-98                Swap                 50,000              $2.01 Mcf             $2.01 Mcf         1-1-99 to 12-31-99
     01-12-98                Swap                120,000              $2.12 Mcf             $2.12 Mcf         1-1-00 to 12-31-00
     02-08-99                Swap                120,000              $2.35 Mcf             $2.35 Mcf         1-1-01 to 12-31-01
</TABLE>




                                       11
<PAGE>   12

         The Company also hedges from time to time the basis for its natural gas
production which depends upon the location of its gas production. Such basis
hedges are immaterial to the financial performance of the Company.

Interest Rate Swap Agreement

         Effective as of December 23, 1997, the Company entered into an interest
rate swap accounted for as a hedge with any realized gains or losses
appropriately recorded as interest expense. The swap consists of a $10 million
notional amount of indebtedness at a fixed swap rate of 6.02 percent based on
the three-month LIBOR for the Company. The term of this swap ends on December
23, 1999. Effective as of January 1, 1999, this interest rate swap was assigned
to BankBoston. In conjunction with such assignment the terms of the swap were
modified to reduce the fixed swap rate from 6.02 percent to 5.65 percent and to
extend the term of the swap until December 23, 2000, at the option of
BankBoston.



                                       12
<PAGE>   13

ITEM 2.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
         RESULTS OF OPERATIONS

FORWARD LOOKING STATEMENTS

         Certain information included in this quarterly report on Form 10-Q and
other materials filed by the Company with the SEC contain forward-looking
statements that involve risks and uncertainties that could cause actual results
to differ from projected results. Such statements address activities, events or
developments that the Company expects, believes, projects, intends or
anticipates will or may occur, including such matters as future capital,
development and exploration expenditures (including the amount and nature
thereof), drilling of wells, reserve estimates (including estimates of future
net revenues associated with such reserves and the present value of such future
net revenues), future production of oil and natural gas, future sales prices for
oil and gas production, business strategies, expansion and acquisition,
obtaining financial or industry partners for prospect or program development, or
marketing of oil and natural gas. Factors that could cause actual results to
differ materially are described, among other places, in this 10-Q and under the
caption "Results of Operations." Without limiting the Cautionary Disclosures so
described, Cautionary Disclosures include, among others: general economic
conditions, the market price of oil and natural gas, the risks associated with
exploration, the Company's ability to find, acquire, market, develop and produce
new properties, operating hazards inherent to the oil and natural gas business,
uncertainties in the estimation of proved reserves and in the projection of
future rates of production and timing of development expenditures, the strength
and financial resources of the Company's competitors, the Company's ability to
find and retain skilled personnel, climatic conditions, labor relations,
availability and cost of material and equipment, environmental risks, the
results of financing efforts, and regulatory developments. All written and oral
forward-looking statements attributable to the Company or persons acting on its
behalf are expressly qualified in their entirety by the Cautionary Disclosures.
The Company disclaims any obligation to update or revise any forward-looking
statement to reflect events or circumstances occurring hereafter or to reflect
the occurrence of anticipated or unanticipated events.

THE FORMATION OF VISTA

         Vista Energy Resources, Inc. (the "Company") is a Delaware corporation
whose common stock is listed and traded on the American Stock Exchange. The
company was formed in May 1998 for the purpose of merging Vista Resources
Partners, L.P. , a Texas limited partnership (the "Vista Partnership"), and
Midland Resources, Inc., a publicly traded Texas corporation ("Midland
Resources"). Such merger occurred on October 28, 1998 (the "Midland Merger").
The Company is an oil and gas exploration and production company with ownership
interests in oil and gas properties located principally in the Permian Basin of
West Texas and Southeastern New Mexico and the onshore Gulf Coast region of
Texas.

         In accordance with the provisions of Accounting Principles Board
("APB") No. 16 Business Combinations, the merger of the Vista Partnership and
Midland Resources was


                                       13
<PAGE>   14

accounted for as a purchase by the Company (formerly the Vista Partnership). As
a result, the historical financial statements for the Company are those of the
Vista Partnership.

FINANCIAL PERFORMANCE

         The Company reported a net income of $.3 million ($ .02 per share) and
$.3 million ($ .02 per share) for the three and six months ended June 30, 1999,
respectively, as compared to a net loss of ($ .2) million ($ .02 per share) and
($ .3) million ($ .03 per share) for the same periods in 1998. As discussed more
fully in "Results of Operations" below, the Company's financial performance for
the six months ended June 30, 1999, was negatively impacted by the following
items: (i) lower (5 percent) oil prices and lower (3 percent) gas prices
received; (ii) increase in gross production costs due to the addition of
properties acquired in the 1998 Acquisitions (hereinafter defined); and (iii) an
increase in interest expense as a result of the additional indebtedness incurred
in respect of the 1998 Acquisitions.

         Net cash provided by operating activities was $ 1.9 million during the
six months ended June 30, 1999, respectively, as compared to net cash provided
by operating activities of $ .6 million for the same period in 1998. This
increase was primarily attributable to increases in production from the
properties acquired in the 1998 Acquisitions and production increases from the
Company's success in its 1998 and 1999 drilling and recompletion program offset
by lower commodity prices for oil and gas and increased production costs and
interest expense as a result of the additional properties acquired and
indebtedness incurred in respect of the 1998 Acquisitions.

         The Company strives to maintain its outstanding indebtedness at a
moderate level in order to provide sufficient financial flexibility to fund
future opportunities. The Company's total book capitalization at June 30, 1999,
was $58.2 million, consisting of total long-term debt of $52.6 million and
owners' equity of $5.6 million. Debt as a percentage of total book
capitalization was 90 percent at June 30, 1999, which was essentially the same
as at December 31, 1998.

DRILLING RESULTS

         During the first six months of 1999, the Company has continued its
emphasis on development, exploration and production activities, with a primary
focus on the exploitation of its current portfolio of drilling locations. During
the first six months of 1999, the Company participated in the drilling and
completion of four gross development wells and three gross exploration wells.
None of these wells were in progress at December 31, 1998. Of the wells
completed during the six months ended June 30, 1999, five were completed
successfully which resulted in a 71 percent success rate. In addition to the
wells completed in the first six months of 1999, the Company had two wells in
progress at June 30, 1999.



                                       14
<PAGE>   15

ACQUISITION ACTIVITIES

         1999 Acquisitions - Although various acquisition candidates were
evaluated during the first six months of 1999, no material acquisitions were
made during such time period.

         1998 Acquisitions - On October 28, 1998, the Midland Merger between the
Vista Partnership and Midland Resources was completed resulting in the formation
of the Company. As a result of the Midland Merger, Midland Resources' security
holders acquired 27.3 percent of the outstanding Common Stock of the Company and
security holders of the Vista Partnership acquired the remaining 72.7 percent of
the outstanding Common Stock of the Company. In addition, upon consummation of
the Midland Merger, the Common Stock of Vista, the newly merged company, became
publicly traded on the American Stock Exchange effective October 29, 1998.

         Effective as of October 1, 1998, the Company acquired working interests
ranging from 65 percent to 85 percent in a group of oil and gas producing leases
from IP Petroleum Company, Inc. and certain of its working interest partners
(the "IP Acquisition"). These leases are located primarily in the War-Wink area
of Ward and Winkler Counties, Texas, and the interests were acquired for a
purchase price of $19.1 million. The IP Acquisition closed on December 18, 1998.
The Midland Merger and the IP Acquisition are sometimes collectively referred to
herein as the "1998 Acquisitions."

RESULTS OF OPERATIONS

         Oil and Gas Production.

<TABLE>
<CAPTION>
                                                     THREE MONTHS ENDED             SIX MONTHS ENDED
                                                          JUNE  30,                     JUNE  30,
                                                  -------------------------     -------------------------
                                                     1999           1998           1999           1998
                                                  ----------     ----------     ----------     ----------
<S>                                               <C>            <C>            <C>            <C>
Revenues ....................................     $4,756,810     $2,003,111     $8,485,051     $4,057,279
Costs and expenses:
  Production costs ..........................      1,659,895        952,802      2,859,738      1,939,530
  Depletion .................................      1,041,825        467,068      2,212,363        962,026
  Exploration costs .........................         27,563             --         38,768             --
                                                  ----------     ----------     ----------     ----------
          Total costs and expenses ..........      2,729,283      1,419,870      5,110,869      2,901,556
                                                  ----------     ----------     ----------     ----------
Operating profit (excluding general and
administrative expenses and income taxes) ...     $2,027,527     $  583,241     $3,374,182     $1,155,723
                                                  ==========     ==========     ==========     ==========
Production:
  Oil (Bbls) ................................        228,627        119,593        450,638        235,773
  Gas (Mcf) .................................        814,010        235,926      1,506,211        477,990
          Total (BOE) .......................        364,295        158,914        701,673        315,438
Average Daily Production:
  Oil (Bbls) ................................          2,512          1,314          2,490          1,303
  Gas (Mcf) .................................          8,945          2,593          8,322          2,641
                                                  ----------     ----------     ----------     ----------
          Total (BOE) .......................          4,003          1,746          3,877          1,743
Average Oil Price (Per Bbl) .................     $    14.08     $    11.87     $    12.63     $    13.28

Average Gas Price (Per Mcf) .................     $     1.82     $     2.47     $     1.83     $     1.92
Costs (Per BOE):
  Lease operating expense ...................     $     3.95     $     4.98     $     3.43     $     5.10
  Production taxes ..........................     $      .61     $     1.02     $      .65     $     1.05
                                                  ----------     ----------     ----------     ----------
          Total production costs ............     $     4.56     $     6.00     $     4.08     $     6.15
  Depletion .................................     $     2.86     $     2.94     $     3.15     $     3.05
</TABLE>


                                       15
<PAGE>   16
         Oil and Gas Revenues. Revenues from oil and gas operations totaled $4.8
million and $8.5 million for the three and six months ended June 30, 1999,
compared to $2.0 and $4.1 million for the same periods in 1998, representing an
increase of 140 percent and 107 percent, respectively. The increase is primarily
attributable to the 1998 Acquisitions and increases in production due to the
Company's successful exploitation activities in 1998 and 1999, offset by
decreased average prices being received for the six month period for both oil
and gas production. The average oil prices received for the three and six months
ended June 30, 1999, was $14.08 and $12.63, respectively, compared to $11.87 and
$13.28 for the three and six months ended June 30, 1998, while the average gas
price received was $1.82 and $1.83 for the three and six months ended June 30,
1999, respectively, compared to $2.47 and $1.92 for the same periods in 1998.

         Average daily oil production increased 91 percent to 2,512 Bbls and
2,490 Bbls for the three and six months of 1999 from 1,314 Bbls and 1,303 Bbls
for the same period of 1998; and average daily gas production increased 245
percent and 215 percent to 8,945 Mcf and 8,322 Mcf from 2,593 Mcf and 2,641 Mcf
for the same period.

         Hedging Activities. The oil and gas prices that the Company reports is
based on the actual prices received for the commodities adjusted for the results
of any of the Company's hedging activities. The Company periodically enters into
commodity derivative contracts (i.e., swaps and collars) in order to (i) reduce
the effect of the volatility of price changes on the commodities the Company
produces and sells; (ii) support the Company's annual capital budgeting and
expenditure plans; and (iii) lock in prices to protect the economics related to
certain capital projects. Set forth below is the contract amount and material
terms of all crude oil hedging instruments held by the Company at June 30, 1999
(monthly volumes are expressed in Bbls and all prices are expressed in the
calendar monthly average of daily NYMEX closing prices for Light Sweet Crude
Oil):

<TABLE>
<CAPTION>

    TRADE DATE        TYPE TRANSACTION       MONTHLY VOLUME       PUT FLOOR PRICE     CALL CEILING PRICE            TERM
    ----------        ----------------       --------------       ---------------     ------------------            ----
<S>                   <C>                    <C>                  <C>                 <C>                    <C>
     12-11-98              Swap                  40,000             $14.20 Bbl            $14.20 Bbl         8-1-99 to 6-30-00
     03-19-99              Swap                  60,000             $14.85 Bbl            $14.85 Bbl         4-1-99 to 7-31-99
     04-19-99              Collar                20,000             $15.00 Bbl            $17.00 Bbl         1-1-00 to 6-30-00
     04-19-99              Collar                40,000             $15.00 Bbl            $16.85 Bbl         7-1-00 to 12-31-00
</TABLE>

         Set forth below is the contract amount and material terms of all NYMEX
natural gas hedging instruments held by the Company at June 30, 1999 (monthly
volumes are expressed in MMBtus and prices are expressed in the monthly NYMEX
(Henry Hub) closing price for natural gas):

<TABLE>
<CAPTION>
    TRADE DATE         TYPE TRANSACTION       MONTHLY VOLUME       PUT FLOOR PRICE      CALL CEILING PRICE           TERM
    ----------         ----------------       --------------       ---------------      ------------------           ----
<S>                    <C>                    <C>                  <C>                  <C>                   <C>
     08-20-98               Collar                40,000              $2.25 Mcf             $2.42 Mcf         1-1-99 to 12-31-99
     11-12-98               Collar                50,000              $2.25 Mcf             $2.51 Mcf         1-1-99 to 12-31-99
     08-20-98               Collar                40,000              $2.17 Mcf             $2.55 Mcf         1-1-99 to 12-31-99
     12-28-98               Swap                  50,000              $2.01 Mcf             $2.01 Mcf         1-1-99 to 12-31-99
     01-12-98               Swap                  120,000             $2.12 Mcf             $2.12 Mcf         1-1-00 to 12-31-00
     02-08-99               Swap                  120,000             $2.35 Mcf             $2.35 Mcf         1-1-01 to 12-31-01
</TABLE>

                                       16
<PAGE>   17

         The Company also hedges from time to time the basis for its natural gas
production which depends upon the location of its gas production. Such basis
hedges are immaterial to the financial performance of the Company.

         Production Costs. Total production costs (inclusive of all lease
operating expenses and production taxes) per BOE decreased 24 percent and 34
percent to $4.56 and $4.08 during the three and six months ended June 30, 1999,
respectively, as compared to production costs per BOE of $6.00 and $6.15 during
the same period of 1998. These reductions are primarily due to the Company's
continued and concentrated efforts to evaluate and reduce all operating costs
and the addition of higher margin properties acquired by the Company in the 1998
Acquisitions.

         Exploration Costs. Exploration costs (which includes abandonments, dry
hole costs, and geological and geophysical costs) increased to $27,563 and
$38,768 during the three and six months of 1999 from $0 during the same periods
in 1998 because the Company incurred certain geological and geophysical costs
during the first six months of 1999.

         General and Administrative Expense. General and administrative expense
was $.6 million and $1.0 million for the three and six months ended June 30,
1999, as compared to $.3 million and $.6 million for the same period ended June
30, 1998, representing an increase of 100 percent and 66 percent for the same
periods, respectively. Such increase was primarily due to the costs associated
with the hiring of additional employees in late 1998 and early 1999 as the
Company's business has grown and due to the Company becoming a publicly traded
company in late 1998. However, on a BOE basis, the Company's general and
administrative expense was $1.97 and $1.97 per BOE for the three and six months
ended June 30, 1998, compared to $1.60 and $1.38 per BOE for the three and six
months ended June 30, 1999.

         Interest Expense. Interest expense was $1.0 million and $2.0 million
and $.4 million and $.7 million for the three and six months ended June 30, 1999
and 1998, respectively. This increase is primarily due to additional borrowings
made in connection with the 1998 Acquisitions.

         Depletion, Depreciation and Amortization Expense. Depletion expense per
BOE increased to $2.86 and $3.15 during the three and six months ended June 30,
1999, as compared to $2.94 and $3.05 during the same period in 1998. The
increase in depletion expense per BOE is primarily related to the additional
properties acquired in the 1998 Acquisitions.

CAPITAL COMMITMENTS, CAPITAL RESOURCES AND LIQUIDITY

         Capital Commitments. The Company's primary needs for cash are for
acquisitions, development and exploration of oil and gas properties, repayment
of principal and interest on outstanding indebtedness and working capital
obligations. The Company's cash expenditures during the first six months of 1999
for additions to oil and gas properties totaled $ 3.3 million. This amount
includes $ 1.0 million for the acquisition of properties and $ 2.3 million for
development and exploratory drilling.


                                       17
<PAGE>   18

         The Company's 1999 capital expenditure drilling budget has been
approved at an amount up to $11.1 million. Pursuant to this budget $9.3 million
has been allocated to exploitation and development activities and $1.8 million
to exploration activities. The Company does not budget for oil and gas property
acquisitions as they are made on a case by case basis as opportunities arise.
The 1999 budget reflects the Company's plans to drill and/or recomplete
approximately 25 oil and gas wells in 1999. The Company currently expects to
fund its 1999 capital expenditure budget primarily with internally generated
cash flow, borrowings under its bank credit facility and proceeds from the sale
of non-strategic assets.

         Capital Resources. The Company's primary capital resources are net cash
provided by operating activities, borrowings under its bank credit facility and
proceeds from the sale of non-strategic assets.

Financing Activities.

         As of June 30, 1999, $52.6 million was outstanding under a $100 million
revolving Credit Agreement dated December 18, 1998, and accompanying note (the
"Credit Facility") with BankBoston subject to a borrowing base which is
redetermined on a semi-annual basis. The borrowing base at June 30, 1999, was
$55 million. The next scheduled borrowing base redetermination is scheduled for
August 31, 1999. Borrowings under the Credit Facility are to be used for the
acquisition and development of oil and gas properties and for other Company
purposes.

         The Company has two options with respect to interest rate elections on
borrowings under the Credit Facility. The Company may either elect an interest
rate equal to (i) the Alternate Base Rate plus the Applicable Margin ("Prime
Basis") or (ii) a Eurodollar rate (i.e., London Interbank Offered Rate) plus the
Applicable Margin ("LIBOR Basis"). The Applicable Margin (as defined in the
Credit Facility) will be adjusted for Borrowing Base usage. The LIBOR Basis
option provides for one-, two-, three-, six- and twelve- month interest periods.
At June 30, 1999, the effective interest rate on the amount outstanding was
7.56 percent.

         Unless otherwise extended by BankBoston, the Credit Facility converts
to a three-year fully amortizing term loan at December 15, 2001.

         The obligations of the Company under the Credit Facility are secured by
a first lien deed of trust on the Company's interests in certain of its oil and
gas properties.

         The Credit Facility contains two financial covenants including a
minimum current ratio, including available borrowings, of 1:1 and an interest
coverage to EBITDA test (2.0 to 1.0 for the four-fiscal quarter period ending
December 31, 1998; 2.25 to 1.0 for the four-fiscal quarter period ending March
31, 1999; and 2.5 to 1.0 for each four-fiscal quarter period thereafter). The
Credit Facility also includes covenants which, among other things, restrict the
incurrence of additional indebtedness and the sale or acquisition of oil and gas
properties above certain levels without the consent of the lender.


                                       18
<PAGE>   19

         Effective as of December 23, 1997, the Company entered into an interest
rate swap accounted for as a hedge with any realized gains or losses
appropriately recorded as interest expense (See Note 7 for further discussion of
hedge accounting.). The swap consists of a $10 million notional amount of
indebtedness at a fixed swap rate of 6.02 percent three-month LIBOR for the
Company. The term of this swap ends on December 23, 1999. Effective as of
January 1, 1999, this interest rate swap was assigned to BankBoston. In
conjunction with such assignment the terms of the swap were modified to reduce
the fixed swap rate from 6.02 percent to 5.65 percent and to extend the term of
the swap until December 23, 2000, at the option of BankBoston.

         Liquidity. At June 30, 1999, the Company had cash of $.8 million on
hand compared to $0 at December 31, 1998. The Company's ratio of current assets
to current liabilities was 1.2:1 at June 30, 1999 and .86:1 at December 31,
1998.

         Year 2000 Readiness Disclosure. "Year 2000," or the ability of computer
systems to process dates with years beyond 1999, affects almost all companies
and organizations. Computer systems that are not Year 2000 compliant by January
1, 2000 may cause material adverse effects to companies and organizations that
rely upon those systems. Continuity of the Company's operations in January 2000
will not only depend upon Year 2000 compliance of the Company's computer systems
and computer-controlled equipment, but also compliance of computer systems and
computer-controlled equipment of third parties. These third parties include oil
and natural gas purchasers and significant service providers such as electric
utility companies and natural gas plant, pipeline and gathering system
operators.

         The Company is in the process of reviewing its computer systems and
computer-controlled field equipment and making the necessary modifications for
Year 2000 compliance. The Company has completed modifications and testing of its
primary accounting and land computer programs. The remaining computer systems
have been inventoried and assessed. Remediation and testing of significant
remaining systems are expected to be complete by September 1999.

         Based on its review, remediation efforts and the results of testing to
date, the Company does not believe that timely modification of its computer
systems and computer-controlled equipment for Year 2000 compliance represents a
material risk to the Company. The Company estimates that total costs related to
Year 2000 compliance efforts will be less than $10,000, of which approximately
$3,600 has been incurred and expensed through June 30, 1999.

         Despite efforts to assure that such third parties are Year 2000
compliant, the Company cannot provide assurance that all significant third
parties will achieve compliance in a timely manner. A third party's failure to
achieve Year 2000 compliance could have a material adverse effect on the
Company's operations and cash flow. The potential effect of Year 2000
non-compliance by third parties is currently unknown.


                                       19
<PAGE>   20

         The Company will develop appropriate contingency plans in the event it
becomes aware of potential problems resulting from failure of the Company's or
of significant third party computer systems on January 1, 2000. The Company has
not developed any contingency plans to date. Specific contingency plans will be
developed in response to the results of testing, which has been completed, as
well as the assessed probability and risk of system or equipment failure. These
contingency plans may include installing backup computer systems or equipment,
temporarily replacing systems or equipment with manual processes, and
identifying alternative suppliers, service companies and purchasers. The Company
expects these plans to be complete by September 30, 1999.

         The failure to correct a material Year 2000 problem could result in an
interruption in, or failure of, certain normal business activities or
operations. Due to the general uncertainty inherent in the Year 2000 problem,
resulting in part from the inability to ensure readiness of third parties, the
Year 2000 compliance issue could have a material adverse impact on the Company's
results of operations and financial condition.



                                       20
<PAGE>   21

                           PART II - OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

         None

ITEM 2. CHANGES IN SECURITIES

         None

ITEM 3. DEFAULTS UPON SENIOR SECURITIES

         None

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

         None

ITEM 5. OTHER INFORMATION

         None

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

(a)      27.1 Financial Data Schedule

(a)      Reports on Form 8-K:

         The Company filed a Current Report on Form 8-K/A dated March 3, 1999
regarding its acquisition of a group of producing oil and gas properties from IP
Petroleum Company.



                                       21
<PAGE>   22

                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.



                                    VISTA ENERGY RESOURCES, INC.



Date: August 10, 1999               By: /s/ C. RANDALL HILL
                                       -----------------------------------------
                                         C. Randall Hill,
                                         Chairman, Chief Executive Officer,
                                         and Chief Financial Officer
                                         (Principal Accounting Officer and
                                         Duly Authorized Officer)


                                       22
<PAGE>   23

                               INDEX TO EXHIBITS

<TABLE>
<CAPTION>
Exhibit No.                        DESCRIPTION
-----------                        -----------
<S>                          <C>
   27.1                      Financial Data Schedule
</TABLE>