# 1990 Athens Open – Singles

Ronald Agénor was the defending champion, but did not participate this year.
Mark Koevermans won the tournament, beating Franco Davín in the final, 5–7, 6–4, 6–1.

## Seeds

* Thomas Muster (second round)
* Emilio Sánchez (first round)
* Guillermo Pérez Roldán (quarterfinals)
* Jordi Arrese (semifinals)
* Franco Davín (final)
* Javier Sánchez (quarterfinals)
* Mark Koevermans (champion)
* Horacio de la Peña (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 | Final |
| | Marián Vajda | 6$^1$ | 6 | 3 | | | | | |
| 5 | Franco Davín | 7$^7$ | 2 | 6 | | | | | |
| 5 | Franco Davín | 7$^7$ | 2 | 6 | 5 | Franco Davín | 7 | 4 | 1 |
| | | | | | 7 | Mark Koevermans | 5 | 6 | 6 |
| 4 | Jordi Arrese | 2 | 6$^4$ | | 7 | Mark Koevermans | 5 | 6 | 6 |
| 7 | Mark Koevermans | 6 | 7$^7$ | | | | | | |

### 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 | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | T Muster | 7 | 6 | | | | | | | | | | | | | | | |
| | M Wostenholme | 6 | 3 | | 1 | T Muster | 6 | 6 | 3 | | | | | | | | | |
| | J Wöhrmann | 2 | 6 | | | M Vajda | 3 | 7 | 6 | | | | | | | | | |
| | M Vajda | 6 | 7 | | | | | | | | M Vajda | 6 | 6 | | | | | |
| | T Carbonell | 7 | 6 | | | | | | | | T Carbonell | 3 | 3 | | | | | |
| Q | MA Gorriz | 6 | 3 | | | T Carbonell | 6 | 6 | | | | | | | | | | |
| | D Pérez | 4 | 4 | | 8 | H de la Peña | 1 | 4 | | | | | | | | | | |
| 8 | H de la Peña | 6 | 6 | | | | | | | | | | | | M Vajda | 6$^1$ | 6 | 3 |
| 3 | G Pérez Roldán | 7 | 6 | 6 | | | | | | | | | | 5 | F Davín | 7$^7$ | 2 | 6 |
| | C Costa | 6 | 7 | 1 | 3 | G Pérez Roldán | 6 | 6 | | | | | | | | | | |
| | J Tarango | 6 | 4 | 6 | | J Tarango | 2 | 3 | | | | | | | | | | |
| WC | S Casal | 3 | 6 | 4 | | | | | | 3 | G Pérez Roldán | 2 | 1 | | | | | |
| | F Luna | 6 | 6 | | | | | | | 5 | F Davín | 6 | 6 | | | | | |
| | M Střelba | 2 | 2 | | | F Luna | 5 | 3 | | | | | | | | | | |
| | R Furlan | 3 | 1 | | 5 | F Davín | 7 | 6 | | | | | | | | | | |
| 5 | F Davín | 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 |
| 6 | J Sánchez | 6 | 6 | 6 | | | | | | | | | | | | | | |
| Q | S Doseděl | 7 | 2 | 3 | 6 | J Sánchez | 6 | 6 | | | | | | | | | | |
| | JF Altur | 3 | 6 | | | L Duncan | 4 | 0 | | | | | | | | | | |
| | L Duncan | 6 | 7 | | | | | | | 6 | J Sánchez | 2 | 3 | | | | | |
| WC | G Kalovelonis | 2 | 2 | | | | | | | 4 | J Arrese | 6 | 6 | | | | | |
| | J Brown | 6 | 6 | | | J Brown | 3 | 6 | | | | | | | | | | |
| Q | G López | 2 | 1 | | 4 | J Arrese | 6 | 7 | | | | | | | | | | |
| 4 | J Arrese | 6 | 6 | | | | | | | | | | | | 4 | J Arrese | 2 | 6$^4$ |
| 7 | M Koevermans | 6 | 6 | | | | | | | | | | | | 7 | M Koevermans | 6 | 7$^7$ |
| | J Cunha-Silva | 4 | 2 | | 7 | M Koevermans | 6 | 4 | 6 | | | | | | | | | |
| | R Azar | 4 | 6 | 2 | WC | A Bavelas | 3 | 6 | 2 | | | | | | | | | |
| WC | A Bavelas | 6 | 3 | 6 | | | | | | 7 | M Koevermans | 3 | 6 | 6 | | | | |
| | F Clavet | 2 | 6 | 6 | | | | | | | F Roig | 6 | 1 | 2 | | | | |
| LL | T Nydahl | 6 | 3 | 2 | | F Clavet | 2 | 7 | 4 | | | | | | | | | |
| | F Roig | 6 | 7 | | | F Roig | 6 | 6 | 6 | | | | | | | | | |
| 2 | E Sánchez | 2 | 6 | | | | | | | | | | | | | | | |