| UTR Pro Tennis Series - Mülheim | 2021/09/23 11:00 | Christos Keisidis v Artem Podorozhnyi | 5-7,2-5 |
| UTR Pro Tennis Series - Mülheim | 2021/09/22 14:00 | Colin Sinclair v Christos Keisidis | 6-3,6-1 |
| UTR Pro Tennis Series - Mülheim | 2021/09/21 08:00 | Edison Ambarzumjan v Christos Keisidis | 6-2,4-6,5-1 |
| UTR Pro Tennis Series - Sófia | 2021/09/03 07:00 | George Lazarov v Christos Keisidis | 6-4,6-4 |
| UTR Pro Tennis Series - Sófia | 2021/09/02 07:00 | Vladimir Popov v Christos Keisidis | 7-6,6-7,3-6 |
| UTR Pro Tennis Series - Sófia | 2021/09/01 08:00 | Christos Keisidis v Mario Radev | 6-1,4-6,6-4 |
| UTR Pro Tennis Series - Sófia | 2021/08/31 08:00 | Christos Keisidis v Josh Sheehy | 4-6,4-6 |
| UTR Pro Tennis Series - Sófia | 2021/08/30 07:00 | Christos Keisidis v Denislav Prodanov | 6-1,5-1 |
| UTR Pro Tennis Series - Mülheim | 2021/09/23 11:00 | Colin Sinclair v Jurriaan Bol | 6-3,6-3 |
| UTR Pro Tennis Series - Mülheim | 2021/09/22 12:30 | Edison Ambarzumjan v Jurriaan Bol | 6-4,2-6,2-6 |
| UTR Pro Tennis Series - Mülheim | 2021/09/20 09:30 | Artem Podorozhnyi v Jurriaan Bol | 7-6,5-3 |
| ITF - M15 Huy | 2021/08/22 15:50 | Thorsten Sollie v Jurriaan Bol | 3-6,6-2,10-2 |