Stadium: Court 1 Round: 62 Ground: Clay
| ITF M25 Marburg | 2021/07/05 10:35 | Christoph Negritu v Dax Donders | 7-6,7-6 |
| ITF M25 The Hague | 2021/06/28 07:50 | Lodewijk Weststrate v Dax Donders | 6-7,6-1,10-5 |
| ITF M25 The Hague | 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 M15 Antalya | 2021/05/09 07:00 | Dax Donders v Alafia Ayeni | 5-7,3-6 |
| ITF M15 Antalya | 2021/05/03 07:00 | Dax Donders v Colin Sinclair | 6-1,3-6,4-10 |