# 1999 Grolsch Open – Singles

Magnus Norman was the defending champion, but the fifth seeded Swede lost in the first round to qualifier Adrian Voinea. Younes El Aynaoui won in the final 6–0, 6–3 against number three seed Mariano Zabaleta and captured the second title of his professional career.

## Seeds

Champion seeds are indicated in bold while text in italics indicates the round in which that seed was eliminated.
* Dominik Hrbatý (first round)
* Nicolás Lapentti (semifinals)
* Mariano Zabaleta (final)
* Fernando Meligeni (quarterfinals)
* Magnus Norman (first round)
* Younes El Aynaoui (champion)
* Andriy Medvedev (second round)
* Marat Safin (semifinals)

## 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 |
| 8 | Marat Safin | 1 | 4 | | | | | |
| 6 | Younes El Aynaoui | 6 | 6 | | | | | |
| 6 | Younes El Aynaoui | 6 | 6 | | 6 | Younes El Aynaoui | 6 | 6 |
| | | | | | 3 | Mariano Zabaleta | 0 | 3 |
| 3 | Mariano Zabaleta | 3 | 7 | 7 | 3 | Mariano Zabaleta | 0 | 3 |
| 2 | Nicolás Lapentti | 6 | 5 | 5 | | | | |

### Section 1

| 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 | D Hrbatý | 2 | 3 | | | | | | | | | | | | | | | |
| | A Di Pasquale | 6 | 6 | | | A Di Pasquale | 7$^7$ | 6 | | | | | | | | | | |
| Q | A Vinceguerra | 1 | 6$^5$ | | | A Pavel | 6$^5$ | 2 | | | | | | | | | | |
| | A Pavel | 6 | 7$^7$ | | | | | | | | A Di Pasquale | 6$^7$ | 6 | 4 | | | | |
| | G Gaudio | 4 | 6 | 6 | | | | | | 8 | M Safin | 7$^9$ | 0 | 6 | | | | |
| | S Sargsian | 6 | 2 | 2 | | G Gaudio | 4 | 6$^4$ | | | | | | | | | | |
| | J van Lottum | 6 | 3 | 5 | 8 | M Safin | 6 | 7$^7$ | | | | | | | | | | |
| 8 | M Safin | 2 | 6 | 7 | | | | | | | | | | | 8 | M Safin | 1 | 4 |
| 4 | F Meligeni | 6 | 7$^7$ | | | | | | | | | | | | 6 | Y El Aynaoui | 6 | 6 |
| WC | A Berasategui | 3 | 6$^1$ | | 4 | F Meligeni | 6 | 7$^7$ | | | | | | | | | | |
| | F Vicente | 6$^2$ | 4 | | SE | A Portas | 3 | 6$^3$ | | | | | | | | | | |
| SE | A Portas | 7$^7$ | 6 | | | | | | | 4 | F Meligeni | 2 | 4 | | | | | |
| SE | J Tarango | 4 | 6$^3$ | | | | | | | 6 | Y El Aynaoui | 6 | 6 | | | | | |
| | K Alami | 6 | 7$^7$ | | | K Alami | 6 | 1 | 1 | | | | | | | | | |
| | S Koubek | 6$^6$ | 3 | | 6 | Y El Aynaoui | 1 | 6 | 6 | | | | | | | | | |
| 6 | Y El Aynaoui | 7$^8$ | 6 | | | | | | | | | | | | | | | |

### Section 2

| 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 |
| 5 | M Norman | 6 | 6$^4$ | 6$^6$ | | | | | | | | | | | | | | | |
| | A Voinea | 4 | 7$^7$ | 7$^8$ | | A Voinea | 6 | 3 | 1 | | | | | | | | | | |
| | M Gustafsson | 2 | 7 | 6 | | M Gustafsson | 3 | 6 | 6 | | | | | | | | | | |
| | B Ulihrach | 6 | 5 | 1 | | | | | | | M Gustafsson | 6$^3$ | 3 | | | | | | |
| | M Puerta | 5 | 1 | | | | | | | 3 | M Zabaleta | 7$^7$ | 6 | | | | | | |
| | F Squillari | 7 | 6 | | | F Squillari | 5 | 4 | | | | | | | | | | | |
| Q | R Sluiter | 3 | 6 | 6$^1$ | 3 | M Zabaleta | 7 | 6 | | | | | | | | | | | |
| 3 | M Zabaleta | 6 | 4 | 7$^7$ | | | | | | | | | | | 3 | M Zabaleta | 3 | 7 | 7 |
| 7 | A Medvedev | 7 | 6 | | | | | | | | | | | | 2 | N Lapentti | 6 | 5 | 5 |
| WC | P Haarhuis | 5 | 3 | | 7 | A Medvedev | 2 | 3 | | | | | | | | | | | |
| | S Schalken | 2 | 6 | 4 | | H Arazi | 6 | 6 | | | | | | | | | | | |
| | H Arazi | 6 | 0 | 6 | | | | | | | H Arazi | 6 | 5 | 3 | | | | | |
| | C Ruud | 6 | 5 | 7 | | | | | | 2 | N Lapentti | 2 | 7 | 6 | | | | | |
| WC | P Wessels | 3 | 7 | 5 | | C Ruud | 5 | 3 | | | | | | | | | | | |
| Q | M Rodríguez | 3 | 2 | | 2 | N Lapentti | 7 | 6 | | | | | | | | | | | |
| 2 | N Lapentti | 6 | 6 | | | | | | | | | | | | | | | | |