| 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 - Ochsenhausen | 2022/06/23 06:30 | Dennis Klein v Sven Happek | W | 3-0 |
| Challenger - Ochsenhausen | 2022/06/20 15:10 | Dennis Klein v Sven Happek | W | 3-1 |
| Challenger - Ochsenhausen | 2022/05/12 12:30 | Dennis Klein v Sven Happek | W | 3-0 |
| Challenger - Ochsenhausen | 2021/12/13 21:00 | Dennis Klein v Sven Happek | W | 3-0 |
| Challenger Series TT | 2023/04/03 09:10 | Pekka Pelz v Dennis Klein | W | 0-3 |
| Challenger Series TT | 2023/04/03 07:10 | Dennis Klein v Amirreza Abbasi | W | 3-2 |
| Challenger Series TT | 2023/03/28 12:50 | Dennis Klein v Dauud Cheaib | W | 3-1 |
| Challenger Series TT | 2023/03/28 10:45 | Dennis Klein v Jeromy Loffler | W | 3-1 |
| Challenger Series TT | 2023/03/28 08:30 | Dennis Klein v Dauud Cheaib | W | 3-1 |
| Challenger Series TT | 2023/03/27 17:10 | Dennis Klein v Jeromy Loffler | W | 3-1 |
| Challenger Series TT | 2023/03/27 14:30 | Makoto Nogami v Dennis Klein | W | 0-3 |
| Challenger Series TT | 2023/03/27 11:50 | Kirill Fadeev v Dennis Klein | W | 0-3 |
| Challenger Series TT | 2023/04/03 11:10 | Dauud Cheaib v Sven Happek | L | 3-0 |
| Challenger Series TT | 2023/04/03 06:30 | Pekka Pelz v Sven Happek | L | 3-0 |
| TT Star Series | 2023/03/25 11:15 | Henning Zeptner v Sven Happek | W | 0-3 |
| TT Star Series | 2023/03/25 08:10 | Sven Happek v Antonin Gavlas | L | 0-3 |
| TT Star Series | 2023/03/24 14:15 | Sven Happek v Michal Obeslo | L | 0-3 |
| TT Star Series | 2023/03/24 12:45 | Boguslav Koszyk v Sven Happek | L | 3-0 |
| TT Star Series | 2023/03/24 10:45 | Oleksandr Tymofieiev v Sven Happek | L | 3-2 |
| TT Star Series | 2023/03/24 08:10 | Jakub Kleprlik v Sven Happek | W | 1-3 |