# 1991 Virginia Slims of Philadelphia – Singles

The last edition of the tournament was in 1979, which was won by Wendy Turnbull.
Monica Seles won the title by defeating Jennifer Capriati 7–5, 6–1 in the final.

## Seeds

The top four seeds received a bye to the second round.
* Monica Seles (champion)
* Gabriela Sabatini (semifinals)
* Arantxa Sánchez Vicario (semifinals)
* Jennifer Capriati (final)
* Mary Joe Fernández (first round)
* Conchita Martínez (quarterfinals)
* Manuela Maleeva-Fragnière (quarterfinals)
* Zina Garrison (quarterfinals)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| 1 | Monica Seles | 6 | 6 | | | | |
| 3 | Arantxa Sánchez Vicario | 1 | 2 | | | | |
| 3 | Arantxa Sánchez Vicario | 1 | 2 | 1 | Monica Seles | 7 | 6 |
| | | | | 4 | Jennifer Capriati | 5 | 1 |
| 4 | Jennifer Capriati | 6 | 6 | 4 | Jennifer Capriati | 5 | 1 |
| 2 | Gabriela Sabatini | 3 | 4 | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | | 1 | M Seles | 7 | 6 | | | | | | | | | | |
| | L Savchenko | 6 | 4 | 6$^7$ | | M Werdel | 5 | 1 | | | | | | | | | | |
| | M Werdel | 4 | 6 | 7$^9$ | | | | | | 1 | M Seles | 7$^8$ | 6 | | | | | |
| | R Fairbank-Nideffer | 3 | 2 | | | | | | | 8 | Z Garrison | 6$^6$ | 0 | | | | | |
| | N Provis | 6 | 6 | | | N Provis | 4 | 4 | | | | | | | | | | |
| | J Moore | 0 | 0 | | 8 | Z Garrison | 6 | 6 | | | | | | | | | | |
| 8 | Z Garrison | 6 | 6 | | | | | | | | | | | | 1 | M Seles | 6 | 6 |
| | | | | | | | | | | | | | | | 3 | A Sánchez Vicario | 1 | 2 |
| | | | | | 3 | A Sánchez Vicario | 6 | 3 | 6 | | | | | | | | | |
| | T Whitlinger | 6 | 7 | | | T Whitlinger | 0 | 6 | 2 | | | | | | | | | |
| | S Stafford | 0 | 5 | | | | | | | 3 | A Sánchez Vicario | 6$^4$ | 6 | 6 | | | | |
| | P Harper | 6 | 6 | | | | | | | | B Schultz | 7$^7$ | 1 | 4 | | | | |
| | Michele Wreem | 3 | 0 | | | P Harper | 3 | 4 | | | | | | | | | | |
| | B Schultz | 6 | 2 | 6 | | B Schultz | 6 | 6 | | | | | | | | | | |
| 5 | MJ Fernández | 1 | 6 | 4 | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 7 | M Maleeva-Fragnière | 6 | 6 | | | | | | | | | | | | | | |
| | E Smylie | 1 | 2 | | 7 | M Maleeva-Fragnière | 6 | 6 | | | | | | | | | |
| | G Helgeson | 0 | 2 | | | A Frazier | 3 | 3 | | | | | | | | | |
| | A Frazier | 6 | 6 | | | | | | | 7 | M Maleeva-Fragnière | 3 | 2 | | | | |
| | L McNeil | 6 | 1 | 6 | | | | | | 4 | J Capriati | 6 | 6 | | | | |
| | E Švíglerová | 1 | 6 | 2 | | L McNeil | 6$^9$ | 7$^7$ | 2 | | | | | | | | |
| | | | | | 4 | J Capriati | 7$^{11}$ | 6$^4$ | 6 | | | | | | | | |
| | | | | | | | | | | | | | | 4 | J Capriati | 6 | 6 |
| 6 | C Martínez | 6 | 6 | | | | | | | | | | | 2 | G Sabatini | 3 | 4 |
| | C Lindqvist | 2 | 4 | | 6 | C Martínez | 6 | 6 | | | | | | | | | |
| | H Suková | 6 | 6 | | | H Suková | 3 | 2 | | | | | | | | | |
| | E Brioukhovets | 3 | 4 | | | | | | | 6 | C Martínez | 3 | 0 | | | | |
| | S Appelmans | 4 | 2 | | | | | | | 2 | G Sabatini | 6 | 6 | | | | |
| | N Zvereva | 6 | 6 | | | N Zvereva | 6$^5$ | 6 | 2 | | | | | | | | |
| | | | | | 2 | G Sabatini | 7$^7$ | 2 | 6 | | | | | | | | |