# 1991 Volvo San Francisco – Singles

Andre Agassi was the defending champion, but lost in semifinals to Brad Gilbert.
Darren Cahill won the title by defeating Gilbert 6–2, 3–6, 6–4 in the final.

## Seeds

* Andre Agassi (semifinals)
* Andrés Gómez (second round)
* Brad Gilbert (final)
* John McEnroe (quarterfinals)
* Tim Mayotte (second round)
* Darren Cahill (champion)
* Wally Masur (semifinals)
* Gary Muller (first 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 | Final |
| 1 | Andre Agassi | 1 | 2 | | | | | | |
| 3 | Brad Gilbert | 6 | 6 | | | | | | |
| 3 | Brad Gilbert | 6 | 6 | | 3 | Brad Gilbert | 2 | 6 | 4 |
| | | | | | 6 | Darren Cahill | 6 | 3 | 6 |
| 6 | Darren Cahill | 4 | 6 | 7 | 6 | Darren Cahill | 6 | 3 | 6 |
| 7 | Wally Masur | 6 | 4 | 5 | | | | | |

### 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 | A Agassi | 7$^7$ | 6 | | | | | | | | | | | | | | | |
| Q | J Tarango | 6$^5$ | 3 | | 1 | A Agassi | 3 | 6 | 6 | | | | | | | | | |
| Q | M Ondruska | 1 | 3 | | | U Riglewski | 6 | 4 | 3 | | | | | | | | | |
| | U Riglewski | 6 | 6 | | | | | | | 1 | A Agassi | 6 | 6 | | | | | |
| | S Davis | 5 | 3 | | | | | | | | K Curren | 2 | 4 | | | | | |
| | K Curren | 7 | 6 | | | K Curren | 4 | 7$^8$ | 6 | | | | | | | | | |
| | L Herrera | 6 | 7$^7$ | | | L Herrera | 6 | 6$^6$ | 2 | | | | | | | | | |
| 8 | G Muller | 4 | 6$^4$ | | | | | | | | | | | | 1 | A Agassi | 1 | 2 |
| 3 | B Gilbert | 6 | 3 | 6 | | | | | | | | | | | 3 | B Gilbert | 6 | 6 |
| | P Kühnen | 3 | 6 | 2 | 3 | B Gilbert | 6 | 6 | | | | | | | | | | |
| | A Mronz | 7$^7$ | 6 | | | A Mronz | 3 | 3 | | | | | | | | | | |
| Q | R Leach | 6$^3$ | 3 | | | | | | | 3 | B Gilbert | 6 | 5 | 6 | | | | |
| | D Goldie | 6 | 5 | 6 | | | | | | | D Goldie | 1 | 7 | 4 | | | | |
| | J Grabb | 4 | 7 | 3 | | D Goldie | 2 | 7$^8$ | 7 | | | | | | | | | |
| | T Carbonell | 4 | 6$^6$ | | 5/WC | T Mayotte | 6 | 6$^6$ | 5 | | | | | | | | | |
| 5/WC | T Mayotte | 6 | 7$^8$ | | | | | | | | | | | | | | | |

### 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 | Semifinals |
| 6 | D Cahill | 6 | 6 | | | | | | | | | | | | | | | | |
| | T Högstedt | 2 | 2 | | 6 | D Cahill | 5 | 6 | 6 | | | | | | | | | | |
| | B Garrow | 1 | 1 | | | G Raoux | 7 | 4 | 3 | | | | | | | | | | |
| | G Raoux | 6 | 6 | | | | | | | 6 | D Cahill | 7 | 3 | 6 | | | | | |
| | M Kratzmann | 6 | 7$^7$ | | | | | | | 4/WC | J McEnroe | 6 | 6 | 3 | | | | | |
| | V Paloheimo | 3 | 6$^1$ | | | M Kratzmann | 4 | 6 | | | | | | | | | | | |
| | A Sznajder | 3 | 0 | | 4/WC | J McEnroe | 6 | 7 | | | | | | | | | | | |
| 4/WC | J McEnroe | 6 | 6 | | | | | | | | | | | | 6 | D Cahill | 4 | 6 | 7 |
| 7 | W Masur | 6 | 6 | | | | | | | | | | | | 7 | W Masur | 6 | 4 | 5 |
| | B Pearce | 1 | 4 | | 7 | W Masur | 6 | 6 | | | | | | | | | | | |
| | R Krishnan | 7$^7$ | 7$^7$ | | | R Krishnan | 3 | 3 | | | | | | | | | | | |
| | A Rahunen | 6$^4$ | 6$^1$ | | | | | | | 7 | W Masur | 6 | 4 | 7 | | | | | |
| | D Pate | 6 | 7 | | | | | | | | D Pate | 1 | 6 | 6 | | | | | |
| WC | P Chamberlin | 3 | 5 | | | D Pate | 1 | 6 | 6 | | | | | | | | | | |
| Q | B Devening | 6 | 4 | 4 | 2 | A Gómez | 6 | 4 | 2 | | | | | | | | | | |
| 2 | A Gómez | 4 | 6 | 6 | | | | | | | | | | | | | | | |