| Bonn Int. Qual | 2023/05/31 09:10 | Kai Niederhuber v David K Kristensen | L | 0-2 |
| Austrian Open Qual | 2023/05/25 09:55 | Kai Niederhuber v Jia Jie Tan | L | 0-2 |
| Slovenia Open Quals | 2023/05/17 16:45 | Kai Niederhuber v Yaro Van Delsen | L | 1-2 |
| Slovenia Open Quals | 2023/05/17 09:10 | Kai Niederhuber v Adarsh Palani Kumar | W | 2-0 |
| Luxembourg Open Qual | 2023/05/04 12:50 | Kai Niederhuber v Bruno Carvalho | L | 0-2 |
| Luxembourg Open Qual | 2023/05/04 10:30 | Ramnish Kumar v Kai Niederhuber | W | 0-2 |
| Polish Open Qual | 2023/03/22 16:00 | Matthias Kicklitz v Kai Niederhuber | L | 2-0 |
| Polish Open Qual | 2023/03/22 08:00 | Daniel Dvorak v Kai Niederhuber | W | 0-2 |