Stadium: Court 1 Round: 26 Ground: Hardcourt indoor
| ITF M25 Esch/Alzette | 2023/07/19 12:05 | Guy Den Heijer v Jan Sebesta | 6-7,7-6,6-3 |
| 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 M25 Esch/Alzette | 2023/07/18 10:10 | Paul Woerner v David Pichler | 2-6,4-6 |
| Challenger Iasi | 2023/07/10 07:00 | Kyrian Jacquet v David Pichler | 6-4,6-2 |
| Challenger Iasi | 2023/07/09 07:30 | Radu Paisvant v David Pichler | 0-6,2-6 |
| ITF M25 Bourg-en-Bresse | 2023/06/27 08:50 | David Pichler v Tiago Pires | 4-6,3-6 |
| Challenger Poznan | 2023/06/18 15:40 | Emilio Nava v David Pichler | 7-6,4-6,6-2 |
| Challenger Bratislava | 2023/06/11 10:00 | Daniel Dutra Da Silva v David Pichler | 2-6,6-2,6-2 |
| ITF M25 Kursumlijska Banja | 2023/06/08 06:55 | David Pichler v Sebastian Prechtel | 2-6,4-6 |
| ITF M25 Kursumlijska Banja | 2023/06/07 16:30 | David Pichler v Ognjen Milic | 6-1,6-3 |