Stadium: Court 2 Round: 25 Ground: Hardcourt indoor
| ITF M25 Esch/Alzette | 2023/07/17 15:20 | Guy Den Heijer v William Jucha | 6-4,7-5 |
| ITF M25 Esch/Alzette | 2023/07/17 08:40 | Guy Den Heijer v Mats Bredschneijder | 4-6,6-2,10-6 |
| ITF M25 Esch/Alzette | 2023/07/10 09:30 | Brian Bozemoj v Guy Den Heijer | 6-2,4-6,16-14 |
| ITF M25 The Hague | 2023/07/07 11:35 | Eric Vanshelboim v Guy Den Heijer | 6-2,6-2 |
| ITF M25 The Hague | 2023/07/06 09:00 | Fons Van Sambeek v Guy Den Heijer | 4-6,6-1,2-6 |
| ITF M15 Alkmaar | 2023/06/25 10:00 | Guy Den Heijer v Stijn Paardekooper | 4-6,6-4,12-14 |
| ITF M15 Saarlouis | 2023/06/22 11:30 | Lodewijk Weststrate v Guy Den Heijer | 7-6,6-4 |
| ITF M15 Saarlouis | 2023/06/21 13:20 | David Fix v Guy Den Heijer | 6-4,6-7,2-6 |
| ITF M25 Klosters | 2023/07/04 07:00 | Jan Sebesta v Dylan Dietrich | 4-6,6-7 |
| ITF M25 Klosters | 2023/07/03 11:15 | Jan Sebesta v Andrin Casanova | 2-6,2-6 |
| ITF M25 Klosters | 2023/07/02 13:00 | Jan Sebesta v Jakob Cadonau | 6-2,6-3 |
| ITF M25 Toulouse | 2023/03/22 13:00 | Loann Massard v Jan Sebesta | 6-1,6-3 |
| ITF M25 Toulouse | 2023/03/21 11:15 | Jan Sebesta v Paul Barbier Gazeu | 3-6,6-2,10-6 |
| ITF M25 Toulouse | 2023/03/20 15:10 | Jan Sebesta v Romain Vial | 6-3,6-2 |
| ITF M25 Trimbach | 2023/03/15 13:05 | Jan Sebesta v Beibit Zhukayev | 6-7,2-6 |
| ITF M25 Trimbach | 2023/03/14 12:40 | Jan Sebesta v Sacha Ouzilou | 7-5,7-5 |