| UTR Pro Tennis Series Mulheim | 2021/09/22 14:00 | Colin Sinclair v Christos Keisidis | 6-3,6-1 |
| UTR Pro Tennis Series Mulheim | 2021/09/21 08:00 | Edison Ambarzumjan v Christos Keisidis | 6-2,4-6,5-1 |
| UTR Pro Tennis Series Sofia | 2021/09/03 07:00 | George Lazarov v Christos Keisidis | 6-4,6-4 |
| UTR Pro Tennis Series Sofia | 2021/09/02 07:00 | Vladimir Popov v Christos Keisidis | 7-6,6-7,3-6 |
| UTR Pro Tennis Series Sofia | 2021/09/01 08:00 | Christos Keisidis v Mario Radev | 6-1,4-6,6-4 |
| UTR Pro Tennis Series Sofia | 2021/08/31 08:00 | Christos Keisidis v Josh Sheehy | 4-6,4-6 |
| UTR Pro Tennis Series Sofia | 2021/08/30 07:00 | Christos Keisidis v Denislav Prodanov | 6-1,5-1 |
| ITF M15 Irákleio | 2021/06/09 08:00 | Antonio Cayetano March v Christos Keisidis | 4-6,7-6,6-2 |
| UTR Pro Tennis Series Mulheim | 2021/09/21 08:00 | Colin Sinclair v Artem Podorozhnyi | 5-7,4-6 |
| UTR Pro Tennis Series Mulheim | 2021/09/20 09:30 | Artem Podorozhnyi v Jurriaan Bol | 7-6,5-3 |
| ITF M15 Tšornomorsk | 2021/09/03 09:10 | Artem Podorozhnyi v Illya Beloborodko | 1-6,6-7 |
| ITF M15 Tšornomorsk | 2021/09/02 11:55 | Artem Podorozhnyi v Dostanbek Tashbulatov | 6-4,3-6,6-3 |
| ITF M15 Tšornomorsk | 2021/08/30 10:30 | Mathieu Scaglia v Artem Podorozhnyi | 5-7,6-3,3-10 |
| ITF M15 Tšornomorsk | 2021/08/30 07:00 | Artem Podorozhnyi v Svyatoslav Ilnytskyy | 6-3,6-4 |
| ITF M15 Tšornomorsk | 2021/08/29 09:30 | Artem Podorozhnyi v Davud Amirov | 6-3,6-1 |
| ITF M15 Novomoskovsk | 2021/05/25 12:30 | Michal Dembek v Artem Podorozhnyi | 6-1,6-2 |