| 2005-10-10 | Vienna | Hard | R32 | 138 |  Jean-Rene Lisnard (Q) | 102 |  Stefan Koubek | 4-6 7-6(5) 6-3 | H2H | 3 | 145 | 2 | 6 | 46.2% | 71.4% | 42.1% | 5/11 |
| 2005-10-03 | Tokyo | Hard | R64 | 96 |  Bjorn Phau | 105 | Stefan Koubek | 6-7(7) 6-4 7-6(5) | H2H | 3 | 144 | 7 | 6 | 50.0% | 57.4% | 49.2% | 4/11 |
| 2005-09-23 | Davis Cup WG PO: AUT vs ECU | Hard | RR | 77 |  Nicolas Lapentti | 106 | Stefan Koubek | 5-7 4-6 6-4 7-6(5) 7-5 | H2H | 5 | - | - | - | - | - | - | - |
| 2005-09-23 | Davis Cup WG PO: AUT vs ECU | Hard | RR | 106 | Stefan Koubek | 665 | Carlos Avellan | 6-3 6-2 | H2H | 3 | - | - | - | - | - | - | - |
| 2005-09-12 | Beijing | Hard | R16 | 33 |  Carlos Moya (8) | 106 | Stefan Koubek | 3-6 6-3 6-2 | H2H | 3 | 89 | 7 | 5 | 52.4% | 76.7% | 51.3% | 3/5 |
| 2005-09-12 | Beijing | Hard | R32 | 106 | Stefan Koubek | 191 |  Ivo Heuberger | 6-3 7-6(6) | H2H | 3 | 100 | 3 | 2 | 67.1% | 69.4% | 54.2% | 1/3 |
| 2005-08-29 | US Open | Hard | R128 | 74 |  Florent Serra | 85 | Stefan Koubek | 6-1 6-4 4-6 6-4 | H2H | 5 | 145 | 1 | 3 | 60.0% | 76.7% | 60.0% | 2/4 |
| 2005-08-22 | New Haven | Hard | R16 | 20 | Tommy Robredo (4) | 86 | Stefan Koubek (Q) | 6-2 6-2 | H2H | 3 | 60 | 3 | 4 | 47.6% | 95.0% | 63.6% | 1/1 |
| 2005-08-22 | New Haven | Hard | R32 | 86 | Stefan Koubek (Q) | 42 | Gael Monfils (16) | 4-6 7-5 7-5 | H2H | 3 | 141 | 3 | 5 | 61.1% | 62.1% | 54.8% | 6/11 |
| 2005-08-22 | New Haven | Hard | R64 | 86 | Stefan Koubek (Q) | 132 |  Bobby Reynolds (WC) | 6-3 6-4 | H2H | 3 | 70 | 8 | 1 | 68.7% | 76.1% | 52.4% | 5/6 |
