# 1990 Yugoslav Open – Singles

The first edition of the ATP tournament in Umag was held from 14 May until 20 May 1990.
Goran Prpić won the title by defeating Goran Ivanišević 6–3, 4–6, 6–4 in the final.

## Seeds

* Goran Prpić (champion)
* Goran Ivanišević (final)
* Mark Koevermans (second round)
* Jens Woehrmann (first round)
* Andrei Cherkasov (semifinals)
* Aki Rahunen (quarterfinals)
* Marián Vajda (second round)
* Thierry Tulasne (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 | Goran Prpić | 7 | 7 | | | | | | |
| | Horacio de la Peña | 6 | 6 | | | | | | |
| | Horacio de la Peña | 6 | 6 | | 1 | Goran Prpić | 6 | 4 | 6 |
| | | | | | 2 | Goran Ivanišević | 3 | 6 | 4 |
| 5/WC | Andrei Cherkasov | 3 | 7 | 4 | 2 | Goran Ivanišević | 3 | 6 | 4 |
| 2 | Goran Ivanišević | 6 | 5 | 6 | | | | | |

### 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 | G Prpić | 6 | 6 | 6 | | | | | | | | | | | | | | |
| Q | E Masso | 7 | 4 | 0 | 1 | G Prpić | 6 | 6 | | | | | | | | | | |
| | M Tauson | 6 | 4 | | | D Perez | 2 | 0 | | | | | | | | | | |
| | D Perez | 7 | 6 | | | | | | | 1 | G Prpić | 6 | 6 | | | | | |
| | R Azar | 6 | 6 | | | | | | | | R Azar | 4 | 4 | | | | | |
| Q | P Dogger | 2 | 3 | | | R Azar | 0 | 7$^7$ | 6 | | | | | | | | | |
| WC | F Cancellotti | 4 | 1 | | 7 | M Vajda | 6 | 6 | 3 | | | | | | | | | |
| 7 | M Vajda | 6 | 6 | | | | | | | | | | | | 1 | G Prpić | 7 | 7 |
| 3 | M Koevermans | 7 | 6 | | | | | | | | | | | | | H de la Peña | 6 | 6 |
| WC | S Hiršzon | 6 | 3 | | 3 | M Koevermans | 6 | 3 | | | | | | | | | | |
| | E Bengoechea | 7 | 2 | 0 | | H de la Peña | 7 | 6 | | | | | | | | | | |
| | H de la Peña | 5 | 6 | 6 | | | | | | | H de la Peña | 5 | 7 | 6 | | | | |
| | N Marques | 4 | 7 | 6 | | | | | | 6 | A Rahunen | 7 | 6 | 1 | | | | |
| | L Jönsson | 6 | 5 | 3 | | N Marques | 6 | 4 | | | | | | | | | | |
| | G Bloom | 5 | 4 | | 6 | A Rahunen | 7 | 6 | | | | | | | | | | |
| 6 | A Rahunen | 7 | 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/WC | A Cherkasov | 6 | 6 | | | | | | | | | | | | | | | |
| Q | J Clavet | 2 | 4 | | 5/WC | A Cherkasov | 6 | 6 | | | | | | | | | | |
| | O Delaître | 6 | 4 | | | F Roig | 3 | 4 | | | | | | | | | | |
| | F Roig | 7 | 6 | | | | | | | 5/WC | A Cherkasov | 6 | 6 | | | | | |
| Q | D Buljević | 6 | 6 | | | | | | | | E Jelen | 2 | 0 | | | | | |
| | J Anderson | 3 | 4 | | Q | D Buljević | 6 | 3 | 6 | | | | | | | | | |
| | E Jelen | 6 | 3 | 6 | | E Jelen | 2 | 6 | 7 | | | | | | | | | |
| 4 | J Woehrmann | 1 | 6 | 0 | | | | | | | | | | 5/WC | A Cherkasov | 3 | 7 | 4 |
| 8 | T Tulasne | 6 | 3 | 1 | | | | | | | | | | 2 | G Ivanišević | 6 | 5 | 6 |
| | J Potier | 3 | 6 | 6 | | J Potier | 2 | 6 | 6 | | | | | | | | | |
| | C Saceanu | 2 | 2 | | | T Benhabiles | 6 | 3 | 7 | | | | | | | | | |
| | T Benhabiles | 6 | 6 | | | | | | | | T Benhabiles | 4 | 6 | | | | | |
| | M Tabares | 4 | 4 | | | | | | | 2 | G Ivanišević | 6 | 7 | | | | | |
| | F Luna | 6 | 6 | | | F Luna | 2 | 3 | | | | | | | | | | |
| | N Pereira | 1 | 4 | | 2 | G Ivanišević | 6 | 6 | | | | | | | | | | |
| 2 | G Ivanišević | 6 | 6 | | | | | | | | | | | | | | | |