Estadio: Ochsenhausen, Germany
| Challenger Series TT | 2023/05/08 17:10 | Sven Happek v Dennis Klein | W | 1-3 |
| Challenger Series TT | 2023/04/03 12:30 | Dennis Klein v Sven Happek | W | 3-1 |
| Challenger Series TT | 2023/03/06 19:30 | Sven Happek v Dennis Klein | W | 1-3 |
| Challenger Series TT | 2023/01/23 07:30 | Sven Happek v Dennis Klein | W | 1-3 |
| Challenger Series TT | 2023/01/09 14:10 | Sven Happek v Dennis Klein | W | 0-3 |
| Challenger Series TT | 2022/07/12 08:30 | Sven Happek v Dennis Klein | W | 1-3 |
| Challenger de Ochsenhausen | 2022/06/23 06:30 | Dennis Klein v Sven Happek | W | 3-0 |
| Challenger de Ochsenhausen | 2022/06/20 15:10 | Dennis Klein v Sven Happek | W | 3-1 |
| Challenger Series TT | 2023/06/19 06:30 | Dennis Klein v Johannes Willeke | W | 3-0 |
| Challenger Series TT | 2023/05/09 12:50 | Humberto Manhani v Dennis Klein | W | 2-3 |
| Challenger Series TT | 2023/05/09 12:05 | Amirreza Abbasi v Dennis Klein | L | 3-1 |
| Challenger Series TT | 2023/05/09 08:30 | Amirreza Abbasi v Dennis Klein | W | 1-3 |
| Challenger Series TT | 2023/05/09 07:10 | Humberto Manhani v Dennis Klein | W | 2-3 |
| Challenger Series TT | 2023/05/08 17:10 | Sven Happek v Dennis Klein | W | 1-3 |
| Challenger Series TT | 2023/05/08 15:10 | Anton Limonov v Dennis Klein | W | 2-3 |
| Challenger Series TT | 2023/05/08 12:30 | Anton Andersson v Dennis Klein | L | 3-1 |
| Challenger Series TT | 2023/06/19 07:10 | Sven Happek v Jose Guillot | L | 1-3 |
| Challenger Series TT | 2023/06/15 09:10 | Norbert Tauler v Sven Happek | L | 3-1 |
| Challenger Series TT | 2023/06/15 07:10 | Sven Happek v Liang Qiu | L | 2-3 |
| Challenger Series TT | 2023/05/23 09:10 | Sven Happek v Albert Vilardell | L | 1-3 |
| Challenger Series TT | 2023/05/22 19:50 | Sven Happek v Aljaz Godec | L | 0-3 |
| Challenger Series TT | 2023/05/22 17:10 | Sven Happek v Kirill Fadeev | L | 1-3 |
| Challenger Series TT | 2023/05/22 14:30 | Michael Engelhardt v Sven Happek | L | 3-1 |
| Challenger Series TT | 2023/05/22 11:50 | Jeromy Loffler v Sven Happek | W | 0-3 |