Stadium: Court 4 Round: 25 Ground: Clay
| ITF M25 Alkmaar | 2021/06/20 18:00 | Deney Wassermann v Niels Visker | 7-6,6-7,10-6 |
| ITF M15 Skopje | 2021/06/02 09:55 | Niels Visker v Ryan Nijboer | 6-4,3-6,4-6 |
| ITF M15 Skopje | 2021/06/01 08:00 | Niels Visker v Tom Gentzsch | 6-4,6-1 |
| ITF M15 Skopje | 2021/05/31 08:00 | Niels Visker v Lazar Milicevic | 6-7,6-3,12-10 |
| ITF M15 Valldoreix | 2021/05/13 10:10 | Rayane Roumane v Niels Visker | 6-4,2-6,6-4 |
| ITF M15 Valldoreix | 2021/05/12 08:00 | Georgii Kravchenko v Niels Visker | 6-7,1-6 |
| ITF M15 Valldoreix | 2021/05/11 08:00 | Niels Visker v Francisco Cabral | 7-5,6-0 |
| ITF M15 Valldoreix | 2021/05/10 09:00 | Pierre Delage v Niels Visker | 4-6,2-6 |
| ITF M25 Alkmaar | 2021/06/22 17:00 | Joao Lucas Reis da Silva v Jelle Sels | 5-7,1-6 |
| ITF M15 Antalya | 2021/06/16 14:05 | Joao Lucas Reis da Silva v Fermin Tenti | 2-6,5-7 |
| ITF M15 Antalya | 2021/06/10 09:10 | Joao Lucas Reis da Silva v Francisco Comesana | 4-6,6-7 |
| ITF M15 Antalya | 2021/06/08 09:15 | Yu Hsiou Hsu v Joao Lucas Reis da Silva | 5-7,6-7 |
| ITF M15 Sarajevo | 2021/06/05 08:30 | Joao Lucas Reis da Silva v Hernan Casanova | 7-6,3-6,1-6 |
| ITF M15 Sarajevo | 2021/06/04 09:00 | Joao Lucas Reis da Silva v Luka Petrovic | 6-3,6-3 |
| ITF M15 Sarajevo | 2021/06/03 12:05 | Joao Lucas Reis da Silva v Michal Novansky | 6-3,6-0 |
| ITF M15 Sarajevo | 2021/06/02 12:20 | Joao Lucas Reis da Silva v Nemanja Malesevic | 6-3,6-4 |