Stadium: AFT Court Round: 62 Ground: Clay
| ITF M15 Huy | 2021/08/24 09:20 | Guillaume Dermiens v Thorsten Sollie | 4-6,3-6 |
| ITF M15 Huy | 2021/08/23 11:35 | Guillaume Dermiens v Charles Tzicas | 6-3,6-0 |
| ITF M15 Huy | 2021/08/22 13:10 | Guillaume Dermiens v Cedric Stanke | 6-3,6-1 |
| ITF M25 Koksijde | 2021/08/17 08:00 | Guillaume Dermiens v Francesco Passaro | 2-6,1-6 |
| ITF M25 Koksijde | 2021/08/16 11:50 | Guillaume Dermiens v Alen Moritz Hodzic | 6-4,6-3 |
| ITF M15 Esch/Alzette | 2021/07/21 14:25 | Guillaume Dermiens v Patrick Kypson | 1-6,3-6 |
| ITF M15 Esch/Alzette | 2021/07/20 12:55 | Guillaume Dermiens v Raphael Calzi | 1-6,6-4,6-4 |
| ITF M15 Esch/Alzette | 2021/07/19 09:00 | Lucas Szewczyk v Guillaume Dermiens | 3-6,2-6 |
| ITF M15 Oldenzaal | 2021/08/15 10:30 | Gosse Panagoulopoulos v Aydan Gomez Osorio | 4-6,4-6 |
| ITF M25 Alkmaar | 2021/06/20 14:00 | Mats Rosenkranz v Gosse Panagoulopoulos | 6-0,6-2 |