Stadium: Court 3 Round: 62 Ground: Hardcourt outdoor
| ITF M25 Heraklion | 2023/11/11 08:30 | Guy Den Heijer v Cezar Cretu | 4-6,4-6 |
| ITF M25 Heraklion | 2023/11/10 09:55 | Harry Wendelken v Guy Den Heijer | 5-7,2-6 |
| ITF M25 Heraklion | 2023/11/08 07:00 | Guy Den Heijer v Mattia Ricci | 6-2,6-1 |
| ITF M25 Heraklion | 2023/11/07 07:30 | Guy Den Heijer v Simon Freund | 6-2,3-6,10-5 |
| ITF M25 Heraklion | 2023/11/06 07:00 | Guy Den Heijer v Evangelos Kypriotis | 6-1,7-5 |
| ITF M25 Heraklion | 2023/11/03 10:20 | Guy Den Heijer v Enrico Dalla Valle | 2-6,1-6 |
| ITF M25 Heraklion | 2023/11/02 08:00 | Guy Den Heijer v Marlon Vankan | 6-3,7-5 |
| ITF M25 Heraklion | 2023/11/01 12:00 | Stefanos Sakellaridis v Guy Den Heijer | 7-5,3-6,6-7 |
| ITF M15 Santo Domingo | 2023/11/12 13:00 | Niklas Grunewald v Emmett Ward | 1-6,1-6 |
| ITF M25 Santo Domingo | 2023/11/06 16:00 | Imran Sibille v Niklas Grunewald | 6-4,7-6 |
| ITF M25 Sharm El Sheikh | 2023/04/10 11:40 | Niklas Grunewald v Gabriele Bosio | 3-6,0-6 |
| ITF M15 Sharm El Sheikh | 2023/04/02 08:00 | Niklas Grunewald v Saveliy Ivanov | 6-7,2-6 |
| ITF M15 Sharm El Sheikh | 2023/03/27 10:30 | Niklas Grunewald v Lars Goran Verwerft | 2-6,3-6 |
| ITF M15 Sharm El Sheikh | 2023/03/26 14:00 | George Gregoriou v Niklas Grunewald | 5-7,0-6 |
| ITF M15 Sharm El Sheikh | 2022/10/10 08:00 | Adrian Mateo Bejenaru v Niklas Grunewald | 6-4,3-6,10-3 |
| ITF M15 Sharm El Sheikh | 2022/10/09 10:00 | Borys Zgola v Niklas Grunewald | 4-6,6-2,12-14 |