Stadium: Swiss Post Court Round: 62 Ground: Clay
| ITF M25 - Eupen | 2021/09/05 10:30 | Dax Donders v Stephan Iserath | 6-2,6-2 |
| ITF M15 - Oldenzaal | 2021/08/15 14:00 | Dax Donders v Arthur Van Der Kooij | 6-1,6-4 |
| ITF M25 - Marburg | 2021/07/05 10:35 | Christoph Negritu v Dax Donders | 7-6,7-6 |
| ITF M25 - Haag | 2021/06/28 07:50 | Lodewijk Weststrate v Dax Donders | 6-7,6-1,10-5 |
| ITF M25 - Haag | 2021/06/27 08:00 | Dax Donders v Zachary Eisinga | 6-2,7-5 |
| ITF M25 - Alkmaar | 2021/06/24 14:55 | Dax Donders v Javier Barranco Cosano | 4-6,2-6 |
| ITF M25 - Alkmaar | 2021/06/23 18:05 | Dax Donders v Amaury Raynel | 5-7,6-3,6-1 |
| ITF M15 - Skopje | 2021/05/30 08:00 | Dax Donders v Taiyo Yamanaka | 4-6,4-6 |
| ITF M25 - Eupen | 2021/09/05 13:30 | Max Van Nunen v Andre Megrabian | 7-5,6-7,11-13 |