| German Championship | 2023/12/07 13:00 | Kai Lemstra v Edison Ambarzumjan | 6-3,6-1 |
| German Championship | 2023/12/06 12:20 | Kai Lemstra v Noel Larwig | 6-2,6-4 |
| ITF M15 Heraklion | 2023/11/24 08:00 | Alastair Gray v Kai Lemstra | 6-3,7-5 |
| ITF M15 Heraklion | 2023/11/22 12:25 | Alexandros Skorilas v Kai Lemstra | 6-7,1-6 |
| ITF M15 Heraklion | 2023/11/16 08:00 | Kai Lemstra v Jakub Nicod | 6-7,6-1,3-6 |
| ITF M15 Heraklion | 2023/11/14 08:30 | Kai Lemstra v Nikolay Nedelchev | 3-6,6-4,6-1 |
| ITF M15 Selva Gardena | 2023/11/01 12:05 | Kai Lemstra v Hynek Barton | 4-6,4-6 |
| ITF M15 Selva Gardena | 2023/10/30 13:20 | Massimo Giunta v Kai Lemstra | 2-6,4-6 |
| German Championship | 2023/12/07 12:00 | Tom Gentzsch v Max Hans Rehberg | 2-6,7-5,3-6 |
| German Championship | 2023/12/06 12:00 | Alen Mujakic v Max Hans Rehberg | 2-6,4-6 |
| Challenger Ismaning | 2023/11/03 16:25 | Lukas Klein v Max Hans Rehberg | 6-3,6-2 |
| Challenger Ismaning | 2023/11/02 16:30 | Mats Rosenkranz v Max Hans Rehberg | 6-7,4-6 |
| Challenger Ismaning | 2023/10/31 18:35 | Max Hans Rehberg v Maxime Cressy | 6-7,6-4,7-6 |
| Challenger Hamburg | 2023/10/16 09:00 | Mukund Sasikumar v Max Hans Rehberg | 6-7,6-1,7-5 |
| Challenger Hamburg | 2023/10/15 12:20 | Sarp Agabigun v Max Hans Rehberg | 1-6,3-6 |
| ITF M15 Forbach | 2023/09/26 16:00 | Max Hans Rehberg v Volodymyr Iakubenko | 3-6,6-3,1-6 |