# 1990 Estoril Open – Women's singles

Isabel Cueto was the defending champion, but lost in the quarterfinals to Federica Bonsignori.
Bonsignori won the title by defeating Laura Garrone 2–6, 6–3, 6–3 in the final.

## Seeds

* Isabel Cueto (quarterfinals)
* Sandra Cecchini (second round)
* Sabine Hack (semifinals)
* Nicole Jagerman (second round)
* Angeliki Kanellopoulou (second round)
* Patricia Tarabini (semifinals)
* Petra Langrová (first round)
* Florencia Labat (second round)

## 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 |
| | Federica Bonsignori | 2 | 7$^7$ | 6 | | | | |
| 3 | Sabine Hack | 6 | 6$^4$ | 4 | | | | |
| 3 | Sabine Hack | 6 | 6$^4$ | 4 | Federica Bonsignori | 2 | 6 | 6 |
| | | | | | Laura Garrone | 6 | 3 | 3 |
| | Laura Garrone | 6 | 6 | | Laura Garrone | 6 | 3 | 3 |
| 6 | Patricia Tarabini | 2 | 2 | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | I Cueto | 6 | 7$^7$ | | | | | | | | | | | | | | | |
| Q | A Kerek | 4 | 6$^3$ | | 1 | I Cueto | 6 | 6 | | | | | | | | | | |
| | E Švíglerová | 6 | 6 | | | E Švíglerová | 4 | 1 | | | | | | | | | | |
| | I Budařová | 2 | 1 | | | | | | 1 | I Cueto | 2 | 6 | 4 | | | | | |
| LL | V Ruano Pascual | 2 | 7$^7$ | 0 | | | | | | F Bonsignori | 6 | 4 | 6 | | | | | |
| | F Bonsignori | 6 | 6$^5$ | 6 | | F Bonsignori | 6 | 6 | | | | | | | | | | |
| WC | S Prazeres | 2 | 6$^3$ | | 5 | A Kanellopoulou | 3 | 1 | | | | | | | | | | |
| 5 | A Kanellopoulou | 6 | 7$^7$ | | | | | | | | | | | | F Bonsignori | 2 | 7$^7$ | 6 |
| 3 | S Hack | 6 | 6 | | | | | | | | | | | 3 | S Hack | 6 | 6$^4$ | 4 |
| | V Martinek | 2 | 1 | | 3 | S Hack | 6 | 6 | | | | | | | | | | |
| | S Dopfer | 2 | 1 | | | P Ritter | 2 | 2 | | | | | | | | | | |
| | P Ritter | 6 | 6 | | | | | | 3 | S Hack | 6 | 6 | | | | | | |
| | C Mothes | 6 | 6 | | | | | | | C Mothes | 3 | 3 | | | | | | |
| | B Romanò | 0 | 1 | | | C Mothes | 6 | 6 | | | | | | | | | | |
| Q | S Farina | 3 | 1 | | 8 | F Labat | 4 | 4 | | | | | | | | | | |
| 8 | F Labat | 6 | 6 | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 7 | P Langrová | 4 | 0 | | | | | | | | | | | | | |
| Q | N Guerrée | 6 | 6 | Q | N Guerrée | 3 | 4 | | | | | | | | | |
| | L Garrone | 6 | 6 | | L Garrone | 6 | 6 | | | | | | | | | |
| WC | T Couto | 2 | 3 | | | | | | L Garrone | 3 | 6 | 6 | | | | |
| | C Tanvier | 3 | 3 | | | | | | E Zardo | 6 | 2 | 1 | | | | |
| | E Zardo | 6 | 6 | | E Zardo | 6 | 6 | | | | | | | | | |
| | P Etchemendy | 2 | 3 | 4 | N Jagerman | 1 | 1 | | | | | | | | | |
| 4 | N Jagerman | 6 | 6 | | | | | | | | | | | L Garrone | 6 | 6 |
| 6 | P Tarabini | 7$^7$ | 6 | | | | | | | | | | 6 | P Tarabini | 2 | 2 |
| | K Kschwendt | 6$^1$ | 2 | 6 | P Tarabini | 6 | 6 | | | | | | | | | |
| | A Vieira | 7 | 6 | | A Vieira | 4 | 2 | | | | | | | | | |
| | S Meier | 5 | 1 | | | | | 6 | P Tarabini | 6 | 4 | 6 | | | | |
| | K Piccolini | 6 | 6 | | | | | | K Piccolini | 2 | 6 | 2 | | | | |
| Q | R Bielsa | 1 | 4 | | K Piccolini | 6 | 6 | | | | | | | | | |
| | L Lásková | 0 | 0 | 2 | S Cecchini | 4 | 1 | | | | | | | | | |
| 2 | S Cecchini | 6 | 6 | | | | | | | | | | | | | |