| Men's singles | |
|---|---|
| 1991 OTB International Open | |
| Champion |  Michael Stich |
| Runner-up |  Emilio Sánchez |
| Score | 6–2, 6–4 |
| Draw | 32 (1WC/4Q/2LL) |
| Seeds | 8 |
Ramesh Krishnan was the defending champion, but lost in the first round this year.
Michael Stich won the tournament, beating Emilio Sánchez in the final, 6–2, 6–4.
Michael Stich (champion) Sergi Bruguera (quarterfinals) Emilio Sánchez (final)
Andrei Cherkasov (quarterfinals) Alexander Volkov (quarterfinals)
Horst Skoff (semifinals)
Todd Woodbridge (quarterfinals) Francisco Clavet (semifinals)| Semifinals | Final | ||||||||||||
| 1 | Michael Stich | 7 | 6 | ||||||||||
| 6 | Horst Skoff | 5 | 1 | ||||||||||
| 1 | Michael Stich | 6 | 6 | ||||||||||
| 3 | Emilio Sánchez | 2 | 4 | ||||||||||
| 3 | Emilio Sánchez | 7 | 6 | ||||||||||
| 8 | Francisco Clavet | 5 | 1 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | M Stich | 78 | 6 | ||||||||||||||||||||||||
| M Woodforde | 66 | 3 | 1 | M Stich | 6 | 6 | |||||||||||||||||||||
| T Carbonell | 4 | 6 | 7 | T Carbonell | 1 | 2 | |||||||||||||||||||||
| P Kühnen | 6 | 3 | 5 | 1 | M Stich | 6 | 6 | ||||||||||||||||||||
| WC |  A Gómez | 6 | 6 | 7 | T Woodbridge | 4 | 2 | ||||||||||||||||||||
 J Eltingh | 4 | 0 | WC | A Gómez | 77 | 4 | 5 | ||||||||||||||||||||
 C Bergström | 1 | 2 | 7 | T Woodbridge | 64 | 6 | 7 | ||||||||||||||||||||
| 7 | T Woodbridge | 6 | 6 | 1 | M Stich | 7 | 6 | ||||||||||||||||||||
| 4 | A Cherkasov | 6 | 6 | 6 | H Skoff | 5 | 1 | ||||||||||||||||||||
 J Tarango | 2 | 3 | 4 | A Cherkasov | 6 | 7 | |||||||||||||||||||||
| R Fromberg | 6 | 6 | R Fromberg | 2 | 5 | ||||||||||||||||||||||
| J Arias | 4 | 3 | 4 | A Cherkasov | 710 | 3 | 62 | ||||||||||||||||||||
 R Krishnan | 3 | 4 | 6 | H Skoff | 68 | 6 | 77 | ||||||||||||||||||||
| Q | C Adams | 6 | 6 | Q | C Adams | 7 | 2 | 63 | |||||||||||||||||||
 W Ferreira | 3 | 77 | 2 | 6 | H Skoff | 5 | 6 | 77 | |||||||||||||||||||
| 6 | H Skoff | 6 | 64 | 6 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 5 | A Volkov | 6 | 6 | ||||||||||||||||||||||||
| D Poliakov | 2 | 1 | 5 | A Volkov | 0 | 79 | 7 | ||||||||||||||||||||
 C Pioline | 2 | 4 | J Sánchez | 6 | 67 | 5 | |||||||||||||||||||||
| J Sánchez | 6 | 6 | 5 | A Volkov | 1 | 5 | |||||||||||||||||||||
| G Raoux | 3 | 1d | 3 | E Sánchez | 6 | 7 | |||||||||||||||||||||
 B Wuyts | 6 | 2 | B Wuyts | 65 | 2 | ||||||||||||||||||||||
| LL | D Adams | 4 | 4 | 3 | E Sánchez | 77 | 6 | ||||||||||||||||||||
| 3 | E Sánchez | 6 | 6 | 3 | E Sánchez | 7 | 6 | ||||||||||||||||||||
| 8 | F Clavet | 7 | 77 | 8 | F Clavet | 5 | 1 | ||||||||||||||||||||
| Q | S Simian | 5 | 64 | 8 | F Clavet | 6 | 6 | ||||||||||||||||||||
| Q |  M Knowles | 6 | 77 | Q | M Knowles | 3 | 0 | ||||||||||||||||||||
| Q |  N Pereira | 4 | 65 | 8 | F Clavet | 6 | 6 | ||||||||||||||||||||
| LL | Jason Netter | 3 | 2 | 2 | S Bruguera | 1 | 4 | ||||||||||||||||||||
| P Haarhuis | 6 | 6 | P Haarhuis | 4 | 6 | 5 | |||||||||||||||||||||
| J Stoltenberg | 6 | 2 | 3 | 2 | S Bruguera | 6 | 3 | 7 | |||||||||||||||||||
| 2 | S Bruguera | 4 | 6 | 6 | |||||||||||||||||||||||
Jim Courier defeated Andre Agassi in the final, 3–6, 6–4, 2–6, 6–1, 6–4 to win the men's singles tennis title at the 1991 French Open.
Michael Stich defeated Boris Becker in the final, 6–4, 7–6(7–4), 6–4 to win the gentlemen's singles tennis title at the 1991 Wimbledon Championships.
Jim Courier defeated Carlos Costa in the final, 7–6(7–3), 6–0, 6–4 to win the men's singles tennis title at the 1992 Italian Open.
Stefan Edberg defeated Michael Stich in the final, 5–7, 6–4, 6–1 to win the singles tennis title at the 1992 ATP German Open.
Michael Stich defeated Andrei Chesnokov in the final, 6–3, 6–7(1–7), 7–6(9–7), 6–4 to win the 1993 Hamburg European Open.
Jim Courier defeated Guy Forget in the final, 4–6, 6–3, 4–6, 6–3, 7–6(7–4) to win the men's singles tennis title at the 1991 Indian Wells Masters.
Karel Nováček defeated Magnus Gustafsson in the final, 6–3, 6–3, 5–7, 0–6, 6–1 to win the singles tennis title at the 1991 Hamburg European Open.
The 1991 German Open was a tennis tournament played on outdoor clay courts and was part of the ATP Super 9 of the 1991 ATP Tour. It took place at the Rothenbaum Tennis Center in Hamburg, Germany, from May 6 through May 13, 1991. Sergio Casal and Emilio Sánchez won in the final against Cássio Motta and Danie Visser, 7–6, 7–6.
Michael Chang defeated Andrei Chesnokov in the final, 6–3, 6–4, 7–5 to win the men's singles tennis title at the 1992 Indian Wells Masters.
Michael Stich was the defending champion, but lost in the second round this year.
Richard Fromberg and Brad Pearce were the defending champions, but Pearce did not participate this year. Fromberg partnered Jason Stoltenberg, losing in the semifinals.
Boris Becker and Guy Forget were the defending champions, but Becker did not participate this year. Forget partnered Henri Leconte.
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.
Rick Leach and Jim Pugh were the defending champions, but lost in the third round this year.
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.
Luke Jensen and Laurie Warder were the defending champions, but lost in semifinals to Petr Korda and Karel Nováček.
Boris Becker and Michael Stich were the defending champions, but Becker did not compete this year. Stich teamed up with Udo Riglewski and lost in quarterfinals to Sergio Casal and Emilio Sánchez.
Sergio Casal and Emilio Sánchez successfully defended their title by defeating Carl-Uwe Steeb and Michael Stich in the final, 5–7, 6–4, 6–3.
Andrei Medvedev was the defending champion, but lost in the semifinals to Michael Stich.
Pieter Aldrich and Danie Visser were the defending champions, but Aldrich did not compete this year. Visser teamed up with Gary Muller and lost in the quarterfinals to Nick Brown and Richard Vogel.