Stadium: CEE Logistic Round: 26 Ground: Clay
| ITF M15 Allershausen | 2023/08/30 15:10 | Johannes Haerteis v Luca Hesselmann | 2-6,6-1,6-4 |
| ITF M25 Ystad | 2023/08/16 08:45 | Valentin Vacherot v Johannes Haerteis | 6-2,6-7,6-4 |
| ITF M15 Frankfurt Am Main | 2023/08/11 12:50 | Lucas Gerch v Johannes Haerteis | 7-5,6-0 |
| ITF M15 Frankfurt Am Main | 2023/08/10 10:55 | Kai Lemstra v Johannes Haerteis | 7-5,4-6,2-6 |
| Challenger Porto | 2023/08/01 16:10 | Johannes Haerteis v Emilio Nava | 6-7,6-7 |
| Challenger Porto | 2023/07/31 10:00 | Hugo Maia v Johannes Haerteis | 5-7,5-7 |
| Challenger Porto | 2023/07/30 10:00 | Johannes Haerteis v Victor Lilov | 6-4,2-6,6-2 |
| ITF M25 Porto | 2023/07/27 11:45 | Johannes Haerteis v Joao Domingues | 6-2,6-7,2-6 |
| ITF M15 Allershausen | 2023/08/30 11:40 | Nicola Kuhn v Hazem Naw | 6-3,4-6,6-2 |
| Challenger Augsburg | 2023/08/21 08:00 | Christoph Negritu v Nicola Kuhn | 2-6,6-3,7-5 |
| Challenger Augsburg | 2023/08/20 08:00 | Nicola Kuhn v Sebastian Gima | 6-1,6-3 |
| Challenger Meerbusch | 2023/08/08 10:25 | Nicola Kuhn v Jan Choinski | 6-7,4-6 |
| ITF M25 Wetzlar | 2023/08/04 12:30 | Nicola Kuhn v Tristan Lamasine | 6-7,4-6 |
| ITF M25 Wetzlar | 2023/08/04 08:00 | Luca Wiedenmann v Nicola Kuhn | 4-6,4-6 |
| ITF M25 Wetzlar | 2023/08/03 08:00 | Nicola Kuhn v Martin Benes | 6-4,6-1 |
| ITF M15 Metzingen | 2023/07/30 11:00 | Nicola Kuhn v Daniel Paty | 6-4,6-1 |