# 1990 Nichirei International Championships – Singles

In the inaugural edition of the tournament, Mary Joe Fernández won the title by defeating 18-year-old Amy Frazier 3–6, 6–2, 6–3 in the final.

## Seeds

The first four seeds received a bye into the second round.
* Martina Navratilova (quarterfinals)
* Monica Seles (quarterfinals)
* Katerina Maleeva (semifinals)
* Mary Joe Fernández (champion)
* Manuela Maleeva-Fragnière (semifinals)
* Jennifer Capriati (quarterfinals)
* Helena Suková (quarterfinals)
* Amy Frazier (final)

## 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 | Semifinals | Final | Final | Final | Final | Final |
| 5 | Manuela Maleeva-Fragnière | 6 | 5 | 4 | | | | | |
| 4 | Mary Joe Fernández | 4 | 7 | 6 | | | | | |
| 4 | Mary Joe Fernández | 4 | 7 | 6 | 4 | Mary Joe Fernández | 3 | 6 | 6 |
| | | | | | 8 | Amy Frazier | 6 | 2 | 3 |
| 3 | Katerina Maleeva | 5 | 4 | | 8 | Amy Frazier | 6 | 2 | 3 |
| 8 | Amy Frazier | 7 | 6 | | | | | | |

### 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 | Semifinals |
| | | | | | 1 | M Navratilova | 6 | 6 | | | | | | | | | | | |
| | S Rehe | 4 | 6 | 6 | | S Rehe | 1 | 3 | | | | | | | | | | | |
| | R White | 6 | 0 | 1 | | | | | | 1 | M Navratilova | 5 | 6 | 3 | | | | | |
| | P Louie Harper | 6 | 6 | | | | | | | 5 | M Maleeva-Fragnière | 7 | 4 | 6 | | | | | |
| | C MacGregor | 3 | 2 | | | P Louie Harper | 2 | 2 | | | | | | | | | | | |
| | T Takagi | 0 | 2 | | 5 | M Maleeva-Fragnière | 6 | 6 | | | | | | | | | | | |
| 5 | M Maleeva-Fragnière | 6 | 6 | | | | | | | | | | | | 5 | M Maleeva-Fragnière | 6 | 5 | 4 |
| | | | | | | | | | | | | | | | 4 | MJ Fernández | 4 | 7 | 6 |
| | | | | | 4 | MJ Fernández | 6 | 6 | | | | | | | | | | | |
| | C Tessi | 6 | 6 | | | C Tessi | 3 | 1 | | | | | | | | | | | |
| | M Javer | 3 | 2 | | | | | | | 4 | MJ Fernández | 6 | 6 | | | | | | |
| | M Werdel | 6 | 6 | | | | | | | 7 | H Suková | 3 | 4 | | | | | | |
| | P Vásquez | 4 | 2 | | | M Werdel | 7$^7$ | 3 | 2 | | | | | | | | | | |
| | A Leand | 2 | 2 | | 7 | H Suková | 6$^4$ | 6 | 6 | | | | | | | | | | |
| 7 | H Suková | 6 | 6 | | | | | | | | | | | | | | | | |

### Bottom half

| 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 |
| 6 | J Capriati | 6 | 7$^7$ | | | | | | | | | | | | | | |
| | M Miyauchi | 4 | 6$^1$ | 6 | J Capriati | 6 | 6 | | | | | | | | | | |
| | M Maleeva | 6 | 6 | | M Maleeva | 2 | 4 | | | | | | | | | | |
| | K Okamoto | 3 | 4 | | | | | | 6 | J Capriati | 6$^4$ | 6 | 6$^3$ | | | | |
| | G Fernández | 6 | 6 | | | | | | 3 | K Maleeva | 7$^7$ | 3 | 7$^7$ | | | | |
| | M Kidowaki | 0 | 2 | | G Fernández | 7$^8$ | 2 | 2 | | | | | | | | | |
| | | | | 3 | K Maleeva | 6$^6$ | 6 | 6 | | | | | | | | | |
| | | | | | | | | | | | | | | 3 | K Maleeva | 5 | 4 |
| 8 | A Frazier | 7$^7$ | 6 | | | | | | | | | | | 8 | A Frazier | 7 | 6 |
| | B Schultz | 6$^4$ | 1 | 8 | A Frazier | 6 | 7 | | | | | | | | | | |
| | J Richardson | 5 | 3 | | E Švíglerová | 2 | 5 | | | | | | | | | | |
| | E Švíglerová | 7 | 6 | | | | | | 8 | A Frazier | 5 | 7 | 6 | | | | |
| | E Pfaff | 6 | 6 | | | | | | 2 | M Seles | 7 | 5 | 2 | | | | |
| | M Jaggard | 3 | 4 | | E Pfaff | 1 | 0 | | | | | | | | | | |
| | | | | 2 | M Seles | 6 | 6 | | | | | | | | | | |