| TennisDirect NK Tennis | 2021/12/17 10:30 | Botic Van De Zandschulp v Guy Den Heijer | 6-3,6-3 |
| UTR Pro Tennis Series Amsterdam | 2021/12/12 08:30 | Guy Den Heijer v Max Houkes | 6-3,1-6,6-6 |
| UTR Pro Tennis Series Amsterdam | 2021/12/11 10:00 | Guy Den Heijer v Deney Wassermann | 6-7,7-6,1-0 |
| UTR Pro Tennis Series Amsterdam | 2021/12/10 08:25 | Rob Van Den Berg v Guy Den Heijer | 3-6,2-6 |
| UTR Pro Tennis Series Amsterdam | 2021/12/09 11:50 | Jip Van Assendelft v Guy Den Heijer | 2-6,2-6 |
| UTR Pro Tennis Series Amsterdam | 2021/12/08 10:00 | Michiel de Krom v Guy Den Heijer | 3-6,3-5 |
| UTR Pro Tennis Series Amsterdam | 2021/12/06 07:00 | Jannis Kahlke v Guy Den Heijer | 7-6,5-7,3-5 |
| ITF M15 Heraklion | 2021/11/24 08:55 | Guy Den Heijer v Arthur Fery | 6-7,2-6 |
| UTR Pro Tennis Series Amsterdam | 2021/11/03 09:00 | Nathan De Veer v Jesse Timmermans | 4-5 |
| UTR Pro Tennis Series Amsterdam | 2021/11/02 12:00 | Maxence Broville v Jesse Timmermans | 6-3,5-4 |
| ITF M15 Monastir | 2021/02/21 10:00 | Leonardo Taddia v Jesse Timmermans | 4-6,2-6 |
| ITF M15 Monastir | 2021/02/15 12:30 | Jesse Timmermans v Valentin Lapalu | 3-6,1-6 |
| ITF M15 Monastir | 2021/02/15 09:00 | Jonas Greif v Jesse Timmermans | 3-6,1-6 |
| ITF M15 Monastir | 2021/02/14 09:00 | Alberto Orso v Jesse Timmermans | 1-6,2-6 |
| ITF M15 Antalya | 2021/01/12 07:00 | Yan Sabanin v Jesse Timmermans | 6-1,6-1 |
| ITF M15 Antalya | 2021/01/11 07:00 | Benedikt Emesz v Jesse Timmermans | 4-6,4-6 |