 Italy: Genoa - Doubles - Main |
|---|
| Quarter-finals | Ballauff P./Osterthun R. | Caratti C./Mordegan F. | 0:2 (1:6, 2:6) | details | 21.06.1990 |
| 1/8-finals | Ballauff P./Osterthun R. | Clavet J. M./Gorriz M. A. | 2:0 (6:4, 6:3) | details | 18.06.1990 |
 Germany: Munich - Doubles - Main |
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| 1/8-finals | Lozano J./Witsken T. | Ballauff P./Osterthun R. | 2:1 (6:7, 6:1, 6:2) | details | 30.04.1990 |
 Brazil: Rio de Janeiro 2 - Doubles - Main |
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| 1/8-finals | Colombo S./Osterthun R. | Camargo R./Kley I. | 0:2 (3:6, 3:6) | details | 02.04.1990 |
 Morocco: Casablanca - Doubles - Main |
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| 1/8-finals | Costa C./Carbonell T. | Osterthun R./Perez-Roldan G. | 2:1 (4:6, 6:2, 6:3) | details | 05.03.1990 |
| Italy: Milan - Doubles - Main |
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| 1/8-finals | Jelen E./Mortensen M. | Colombo S./Osterthun R. | 2:0 (6:4, 6:4) | details | 05.02.1990 |
 Australia: Australian Open - Doubles - Main |
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| 1/16-finals | Novacek K./Osterthun R. | Connell G./Michibata G. | 0:2 (2:6, 1:6) | details | 17.01.1990 |
| 1/32-finals | Novacek K./Osterthun R. | Custer B./Tyson D. | 2:1 (3:6, 6:3, 7:6) | details | 15.01.1990 |
 New Zealand: Auckland - Doubles - Main |
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| Quarter-finals | DeVries S./MacPherson D. | Ballauff P./Osterthun R. | 2:1 (3:6, 6:0, 6:4) | details | 11.01.1990 |
| 1/8-finals | Mora A./Schor J. | Ballauff P./Osterthun R. | 1:2 (6:7, 6:4, 6:7) | details | 08.01.1990 |
| New Zealand: Wellington - Doubles - Main |
|---|
| 1/8-finals | Ballauff P./Osterthun R. | Van't Hof R./Wekesa P. | 0:2 (1:6, 4:6) | details | 01.01.1990 |
Austria: Kitzbuhel - Singles - Main