# 1991 Czechoslovak Open – Singles

The 1991 PCzechoslovak Open was a men's tennis tournament played on Clay in Prague, Czech Republic that was part of the International Series of the 1991 ATP Tour. Jordi Arrese was the defending champion but lost in the second round to Thomas Muster.
Karel Nováček won the title by defeating Magnus Gustafsson 7–6$^{(7–5)}$, 6–2 in the final.

## Seeds

* Magnus Gustafsson (final)
* Karel Nováček (champion)
* Goran Prpić (first round)
* Horst Skoff (quarterfinals)
* Jordi Arrese (second round)
* Guillermo Pérez Roldán (semifinals)
* Horacio de la Peña (quarterfinals)
* Nicklas Kulti (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 |
| 1 | Magnus Gustafsson | 7 | 6$^5$ | 6 | | | | |
| 6 | Guillermo Pérez Roldán | 5 | 7$^7$ | 2 | | | | |
| 6 | Guillermo Pérez Roldán | 5 | 7$^7$ | 2 | 1 | Magnus Gustafsson | 6$^5$ | 2 |
| | | | | | 2 | Karel Nováček | 7$^7$ | 6 |
| | Thomas Muster | 1 | 6 | 5 | 2 | Karel Nováček | 7$^7$ | 6 |
| 2 | Karel Nováček | 6 | 2 | 7 | | | | |

### 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 | M Gustafsson | 6 | 6 | | | | | | | | | | | | | | | |
| Q | Lukas Thomas | 3 | 2 | | 1 | M Gustafsson | 6 | 6 | | | | | | | | | | |
| | M Filippini | 1 | 2 | | | C Costa | 4 | 1 | | | | | | | | | | |
| | C Costa | 6 | 6 | | | | | | 1 | M Gustafsson | 6 | 6 | | | | | | |
| | P Rebolledo | 4 | 1 | | | | | | | A Boetsch | 2 | 2 | | | | | | |
| Q | L Pimek | 6 | 6 | | Q | L Pimek | 2 | 3 | | | | | | | | | | |
| | A Boetsch | 6 | 6 | | | A Boetsch | 6 | 6 | | | | | | | | | | |
| 8 | N Kulti | 1 | 4 | | | | | | | | | | | 1 | M Gustafsson | 7 | 6$^5$ | 6 |
| 4 | H Skoff | 6 | 6 | | | | | | | | | | | 6 | G Pérez Roldán | 5 | 7$^7$ | 2 |
| WC | R Vašek | 1 | 1 | | 4 | H Skoff | 6 | 6 | | | | | | | | | | |
| | D Poliakov | 3 | 6 | 6 | | D Poliakov | 4 | 1 | | | | | | | | | | |
| Q | M Trněný | 6 | 3 | 2 | | | | | 4 | H Skoff | 6 | 4 | 6$^2$ | | | | | |
| | R Azar | 4 | 4 | | | | | | 6 | G Pérez Roldán | 3 | 6 | 7$^7$ | | | | | |
| | CU Steeb | 6 | 6 | | | CU Steeb | 4 | 0 | | | | | | | | | | |
| | JF Altur | 4 | 4 | | 6 | G Pérez Roldán | 6 | 6 | | | | | | | | | | |
| 6 | G Pérez Roldán | 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 | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 5 | J Arrese | 6 | 6 | | | | | | | | | | | | | | | |
| | F Davín | 2 | 2 | | 5 | J Arrese | 2 | 3 | | | | | | | | | | |
| | D Nargiso | 4 | 2 | | | T Muster | 6 | 6 | | | | | | | | | | |
| | T Muster | 6 | 6 | | | | | | | | T Muster | 6 | 6 | | | | | |
| Q | P Vojtíšek | 5 | 3 | | | | | | | | M Larsson | 3 | 0 | | | | | |
| WC | K Kučera | 7 | 6 | | WC | K Kučera | 1 | 0 | | | | | | | | | | |
| | M Larsson | 6 | 6 | | | M Larsson | 6 | 6 | | | | | | | | | | |
| 3 | G Prpić | 2 | 4 | | | | | | | | | | | | T Muster | 1 | 6 | 5 |
| 7 | H de la Peña | 6$^3$ | 6 | 6 | | | | | | | | | | 2 | K Nováček | 6 | 2 | 7 |
| | P Arraya | 7$^7$ | 0 | 2 | 7 | H de la Peña | 6 | 6 | | | | | | | | | | |
| | J Aguilera | 6 | 6 | | | J Aguilera | 2 | 3 | | | | | | | | | | |
| WC | J Kodeš Jr. | 3 | 4 | | | | | | | 7 | H de la Peña | 0 | 4 | | | | | |
| | A Olhovskiy | 6$^3$ | 7 | 4 | | | | | | 2 | K Nováček | 6 | 6 | | | | | |
| | R Furlan | 7$^7$ | 5 | 6 | | R Furlan | 6 | 4 | 6$^5$ | | | | | | | | | |
| | V Paloheimo | 4 | 3 | | 2 | K Nováček | 4 | 6 | 7$^7$ | | | | | | | | | |
| 2 | K Nováček | 6 | 6 | | | | | | | | | | | | | | | |