# 1991 Puerto Rico Open – Singles

Jennifer Capriati was the defending champion, but did not compete this year.
Julie Halard won the title by defeating Amanda Coetzer 7–5, 7–5 in the final.

## Seeds

* Gigi Fernández (quarterfinals)
* Julie Halard (champion)
* Sabine Appelmans (semifinals)
* Mary Pierce (semifinals)
* Barbara Rittner (quarterfinals)
* Susan Sloane-Lundy (quarterfinals)
* Florencia Labat (second round)
* Federica Bonsignori (withdrew)

## 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 |
| | Amanda Coetzer | 3 | 6 | 7 | | | | |
| 3 | Sabine Appelmans | 6 | 3 | 5 | | | | |
| 3 | Sabine Appelmans | 6 | 3 | 5 | | Amanda Coetzer | 5 | 5 |
| | | | | | 2 | Julie Halard | 7 | 7 |
| 4 | Mary Pierce | 5 | 1 | | 2 | Julie Halard | 7 | 7 |
| 2 | Julie Halard | 7 | 6 | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | G Fernández | 6 | 4 | 6 | | | | | | | | | | | | | |
| | P Ritter | 1 | 6 | 4 | 1 | G Fernández | 6 | 6 | | | | | | | | | |
| Q | C Benjamin | 6 | 6 | | Q | C Benjamin | 4 | 3 | | | | | | | | | |
| Q | A Schwartz | 4 | 4 | | | | | | 1 | G Fernández | 4 | 2 | | | | | |
| | E Viqueira | 1 | 0 | | | | | | | A Coetzer | 6 | 6 | | | | | |
| | A Coetzer | 6 | 6 | | | A Coetzer | 6 | 6 | | | | | | | | | |
| | R Alter | 6 | 6 | | | R Alter | 2 | 2 | | | | | | | | | |
| Q | J Watanabe | 2 | 1 | | | | | | | | | | | A Coetzer | 3 | 6 | 7 |
| 3 | S Appelmans | 7 | 6 | | | | | | | | | | 3 | S Appelmans | 6 | 3 | 5 |
| | R Hiraki | 5 | 2 | | 3 | S Appelmans | 6 | 6 | | | | | | | | | |
| | L Corsato | 3 | 6 | 5 | | D Faber | 4 | 1 | | | | | | | | | |
| | D Faber | 6 | 4 | 7 | | | | | 3 | S Appelmans | 6 | 6 | | | | | |
| LL | M Drake | 6 | 2 | 6 | | | | | 6 | S Sloane-Lundy | 4 | 1 | | | | | |
| | R Baranski | 1 | 6 | 2 | LL | M Drake | 0 | 3 | | | | | | | | | |
| | V Martinek | 0 | 1 | | 6 | S Sloane-Lundy | 6 | 6 | | | | | | | | | |
| 6 | S Sloane-Lundy | 6 | 6 | | | | | | | | | | | | | | |

### 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 7 | F Labat | 6 | 3 | 6 | | | | | | | | | | | | | | |
| | L Allen | 1 | 6 | 4 | 7 | F Labat | 1 | 0 | | | | | | | | | | |
| | A Leand | 2 | 1 | | | C Cunningham | 6 | 6 | | | | | | | | | | |
| | C Cunningham | 6 | 6 | | | | | | | | C Cunningham | 6 | 1 | 2 | | | | |
| | P Thorén | 6$^1$ | 3 | | | | | | | 4 | M Pierce | 3 | 6 | 6 | | | | |
| | S Rehe | 7$^7$ | 6 | | | S Rehe | 3 | 6 | 5 | | | | | | | | | |
| | A Grossman | 3 | 1 | | 4 | M Pierce | 6 | 0 | 7 | | | | | | | | | |
| 4 | M Pierce | 6 | 6 | | | | | | | | | | | | 4 | M Pierce | 5 | 1 |
| 5 | B Rittner | 6 | 6 | | | | | | | | | | | | 2 | J Halard | 7 | 6 |
| | A Gavaldón | 3 | 3 | | 5 | B Rittner | 6 | 7 | | | | | | | | | | |
| | A Keller | 6 | 6 | | | A Keller | 4 | 5 | | | | | | | | | | |
| | S Stafford | 3 | 3 | | | | | | | 5 | B Rittner | 7 | 1 | 6$^4$ | | | | |
| | M Strandlund | 6 | 2 | 1 | | | | | | 2 | J Halard | 5 | 6 | 7$^7$ | | | | |
| Q | C Kuhlman | 3 | 6 | 6 | Q | C Kuhlman | 4 | 4 | | | | | | | | | | |
| | S Hack | 3 | 4 | | 2 | J Halard | 6 | 6 | | | | | | | | | | |
| 2 | J Halard | 6 | 6 | | | | | | | | | | | | | | | |