| Singles | |
|---|---|
| 1989 Mercedes Cup | |
| Champion |  Martín Jaite |
| Runner-up |  Goran Prpić |
| Score | 6–3, 6–2 |
| Draw | 48 (4WC/6Q) |
| Seeds | 16 |
Andre Agassi was the defending champion, but did not compete this year.
Martín Jaite won the title by defeating Goran Prpić 6–3, 6–2 in the final. [1]
All seeds received a bye into the second round.
Jakob Hlasek (second round) Alberto Mancini (third round)
Aaron Krickstein (third round) Kevin Curren (third round)
Miloslav Mečíř (second round)
Mikael Pernfors (third round) Guillermo Pérez Roldán (quarterfinals)
Sergi Bruguera (semifinals)
John Fitzgerald (second round)
Andrés Gómez (second round)
Ronald Agénor (third round) Jordi Arrese (quarterfinals) Darren Cahill (second round) Martín Jaite (champion)
Alexander Volkov (second round) Jan Gunnarsson (third round)| Quarterfinals | Semifinals | Final | ||||||||||||||||||
| WC |  Jens Wöhrmann | 6 | 6 | |||||||||||||||||
| 7 | Guillermo Pérez Roldán | 3 | 3 | |||||||||||||||||
| WC | Jens Wöhrmann | 7 | 4 | 3 | ||||||||||||||||
| 14 | Martín Jaite | 5 | 6 | 6 | ||||||||||||||||
| 14 | Martín Jaite | 3 | 7 | 6 | ||||||||||||||||
| 12 | Jordi Arrese | 6 | 5 | 4 | ||||||||||||||||
| 14 | Martín Jaite | 6 | 6 | |||||||||||||||||
| Goran Prpić | 3 | 2 | ||||||||||||||||||
| Goran Prpić | 7 | 6 | 6 | |||||||||||||||||
 Alex Antonitsch | 6 | 7 | 3 | |||||||||||||||||
| Goran Prpić | 3 | 7 | 6 | |||||||||||||||||
| 8 | Sergi Bruguera | 6 | 5 | 1 | ||||||||||||||||
| 8 | Sergi Bruguera | 6 | 6 | |||||||||||||||||
 Martin Wostenholme | 1 | 4 | ||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 1 | J Hlasek | 4 | 6 | 3 | |||||||||||||||||||||||
| WC | J Wöhrmann | 6 | 4 | 7 | WC | J Wöhrmann | 6 | 4 | 6 | ||||||||||||||||||
| B Orešar | 2 | 6 | 6 | WC | J Wöhrmann | 6 | 6 | ||||||||||||||||||||
| Q | M Ostoja | 4 | 3 | 16 | J Gunnarsson | 4 | 4 | ||||||||||||||||||||
 F Cancellotti | 6 | 6 | F Cancellotti | 1 | 6 | 3 | |||||||||||||||||||||
| 16 | J Gunnarsson | 6 | 3 | 6 | |||||||||||||||||||||||
| WC | J Wöhrmann | 6 | 6 | ||||||||||||||||||||||||
| 7 | G Pérez Roldán | 3 | 3 | ||||||||||||||||||||||||
| 10 | A Gómez | 6 | 6 | 6 | |||||||||||||||||||||||
| Q | M Zillner | 6 | 3 | Q |  F Santoro | 7 | 2 | 7 | |||||||||||||||||||
| Q | F Santoro | 7 | 6 | Q | F Santoro | 1 | 6 | 3 | |||||||||||||||||||
| S Colombo | 1 | 7 | 6 | 7 | G Pérez Roldán | 6 | 3 | 6 | |||||||||||||||||||
| O Delaître | 6 | 6 | 1 | S Colombo | 1 | 6 | |||||||||||||||||||||
| 7 | G Pérez Roldán | 6 | 7 | ||||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 3 | A Krickstein | 6 | 6 | ||||||||||||||||||||||||
| Q | S Doseděl | 0 | 7 | 2 | Q | L Koslowski | 2 | 3 | |||||||||||||||||||
| Q | L Koslowski | 6 | 5 | 6 | 3 | A Krickstein | 1 | 6 | 2 | ||||||||||||||||||
| L Duncan | 0 | 6 | 3 | 14 | M Jaite | 6 | 4 | 6 | |||||||||||||||||||
| Q | P Korda | 6 | 0 | 6 | Q | P Korda | 3 | 1 | |||||||||||||||||||
| 14 | M Jaite | 6 | 6 | ||||||||||||||||||||||||
| 14 | M Jaite | 3 | 7 | 6 | |||||||||||||||||||||||
| 12 | J Arrese | 6 | 5 | 4 | |||||||||||||||||||||||
| 12 | J Arrese | 6 | 6 | ||||||||||||||||||||||||
| T Tulasne | 7 | 7 | T Tulasne | 0 | 4 | ||||||||||||||||||||||
| WC | T Šmíd | 6 | 6 | 12 | J Arrese | 6 | 6 | ||||||||||||||||||||
| M Davis | 6 | 6 | 1 | 6 | M Pernfors | 4 | 3 | ||||||||||||||||||||
| A Cherkasov | 1 | 7 | 6 | A Cherkasov | 5 | 2 | |||||||||||||||||||||
| 6 | M Pernfors | 7 | 6 | ||||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 5 | M Mečíř | 0 | 3 | ||||||||||||||||||||||||
 C Motta | 3 | 2 | G Prpić | 6 | 6 | ||||||||||||||||||||||
| G Prpić | 6 | 6 | G Prpić | 1 | 6 | 6 | |||||||||||||||||||||
| M Stich | 7 | 6 | 11 | R Agénor | 6 | 4 | 1 | ||||||||||||||||||||
| F Luna | 5 | 2 | M Stich | 6 | 1 | 4 | |||||||||||||||||||||
| 11 | R Agénor | 4 | 6 | 6 | |||||||||||||||||||||||
| G Prpić | 7 | 6 | 6 | ||||||||||||||||||||||||
| A Antonitsch | 6 | 7 | 3 | ||||||||||||||||||||||||
| 13 | D Cahill | 4 | 1 | ||||||||||||||||||||||||
 S Matsuoka | 6 | 6 | 1 | A Antonitsch | 6 | 6 | |||||||||||||||||||||
| A Antonitsch | 7 | 3 | 6 | A Antonitsch | 5 | 6 | 6 | ||||||||||||||||||||
| B Drewett | 3 | 2 | 4 | K Curren | 7 | 4 | 0 | ||||||||||||||||||||
| H de la Peña | 6 | 6 | H de la Peña | 3 | 4 | ||||||||||||||||||||||
| 4 | K Curren | 6 | 6 | ||||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 8 | S Bruguera | 6 | 6 | ||||||||||||||||||||||||
| WC | M Sinner | 6 | 7 | WC | M Sinner | 3 | 4 | ||||||||||||||||||||
| É Winogradsky | 4 | 5 | 8 | S Bruguera | 6 | 4 | 6 | ||||||||||||||||||||
| M Vajda | 3 | 6 | 6 | M Vajda | 2 | 6 | 1 | ||||||||||||||||||||
| WC | M Tideman | 6 | 1 | 2 | M Vajda | 6 | 6 | ||||||||||||||||||||
| 9 | J Fitzgerald | 0 | 4 | ||||||||||||||||||||||||
| 8 | S Bruguera | 6 | 6 | ||||||||||||||||||||||||
| M Wostenholme | 1 | 4 | |||||||||||||||||||||||||
| 15 | A Volkov | 4 | 5 | ||||||||||||||||||||||||
| M Wostenholme | 6 | 7 | M Wostenholme | 6 | 7 | ||||||||||||||||||||||
| E Bengoechea | 3 | 6 | M Wostenholme | 6 | 6 | ||||||||||||||||||||||
| M Střelba | 6 | 6 | 2 | A Mancini | 2 | 2 | |||||||||||||||||||||
 M Filippini | 7 | 7 | M Filippini | 3 | 6 | ||||||||||||||||||||||
| 2 | A Mancini | 6 | 7 | ||||||||||||||||||||||||
Andrés Gómez defeated Andre Agassi in the final, 6–3, 2–6, 6–4, 6–4 to win the men's singles tennis title at the 1990 French Open. He became the first Ecuadorian, male or female, to win a major, and this was his only major title in singles. Agassi later alleged in his 2009 autobiography that his defeat in the final was partly due to issues with his wig.
Pete Sampras defeated Andre Agassi in the final, 6–4, 6–3, 6–2 to win the men's singles tennis title at the 1990 US Open. It was his first major title, and the first of a then-record 14 men's singles major titles overall.
Andre Agassi defeated Stefan Edberg in the final, 6–1, 6–4, 0–6, 6–2 to win the men's singles tennis title at the 1990 Miami Open.
Boris Becker was the defending champion but lost in the third round to Jan Gunnarsson.
Mark Koevermans was the defending champion, but lost in the quarterfinals this year.
Jim Courier defeated David Wheaton in the final, 4–6, 6–3, 6–4 to win the men's singles tennis title at the 1991 Miami Open.
Emilio Sánchez won the men's singles tennis title at the 1991 Italian Open after Alberto Mancini retired from the final, with the scoreline at 6–3, 6–1, 3–0.
Ivan Lendl was the defending champion, but lost in third round to Joakim Nyström.
Andrés Gómez was the defending champion, but lost in the quarterfinals to Aaron Krickstein.
Miloslav Mečíř was the defending champion, but lost in the third round to Thomas Muster.
Emilio Sánchez was the defending champion, but lost in the second round to Francisco Roig.
Mats Wilander was the defending champion, but did not compete this year.
Sergio Casal and Emilio Sánchez were the defending champions, but none competed this year. Sánchez opted to rest after winning at Stuttgart in the previous week, alongside Wally Masur.
Horacio de la Peña was the defending champion, but lost in the third round to Francisco Clavet.
Goran Ivanišević was the defending champion, but lost in the second round to Andrés Gómez.
Kent Carlsson was the defending champion but was forced to forfeit the rest of the season, due to a knee injury that was suffered in August.
Yannick Noah was the defending champion, but lost in the final to Andrés Gómez. The score was 6–4, 7–6(7–5), 7–6(7–1).
The first edition of the ATP tournament in Umag was held from 14 May until 20 May 1990.
Martín Jaite was the defending champion, but lost in the second round to Karel Nováček.
Kent Carlsson was the defending champion, but lost in the second round to Christian Saceanu.
Martín Jaite was the first player who won the tournament (1986, def. swedish Jonas Svensson) and the only one who celebrated twice on this court (1989, def. croatian Goran Prpic)