| UTR Pro Tennis Series - Zadar | 2021/10/01 08:00 | Christos Keisidis v Drazen Petrovic | 6-4,6-4 |
| UTR Pro Tennis Series - Zadar | 2021/09/30 09:30 | Christos Keisidis v Stefanos Sakellaridis | 4-6,6-4,6-4 |
| UTR Pro Tennis Series - Zadar | 2021/09/29 08:00 | Duje Kekez v Christos Keisidis | 6-2,2-6,5-6 |
| UTR Pro Tennis Series - Zadar | 2021/09/28 12:30 | Janos Fekete v Christos Keisidis | 6-4,5-3 |
| UTR Pro Tennis Series - Mulheim | 2021/09/25 10:30 | Christos Keisidis v Lawrence Bataljin | 6-4,5-3 |
| UTR Pro Tennis Series - Mulheim | 2021/09/24 08:00 | Christos Keisidis v Jurriaan Bol | 1-6,4-6 |
| UTR Pro Tennis Series - Mulheim | 2021/09/23 11:00 | Christos Keisidis v Artem Podorozhnyi | 5-7,2-5 |
| UTR Pro Tennis Series - Mulheim | 2021/09/22 14:00 | Colin Sinclair v Christos Keisidis | 6-3,6-1 |
| UTR Pro Tennis Series - Zadar | 2021/10/01 09:30 | Maxim Krapivin v Ivan Denisov | 5-7,3-6 |
| UTR Pro Tennis Series - Zadar | 2021/09/30 12:00 | Deni Zmak v Ivan Denisov | 2-6,6-2,6-5 |
| UTR Pro Tennis Series - Zadar | 2021/09/28 11:00 | Ivan Liutarevich v Ivan Denisov | 3-6,2-6 |
| UTR Pro Tennis Series - Zadar | 2021/09/27 11:00 | Ivan Denisov v Michalis Sakellaridis | 6-2,5-1 |
| ITF - M15 Shymkent | 2021/06/02 05:00 | Ivan Denisov v Beibit Zhukayev | 2-6,2-6 |
| ITF - M15 Shymkent | 2021/06/01 07:00 | Ivan Denisov v Olimjon Nabiev | 7-5,6-4 |
| ITF - M15 Shymkent | 2021/05/31 09:35 | Ibrokhimjon Urinov v Ivan Denisov | 1-6,1-6 |
| ITF - M15 Shymkent | 2021/05/25 04:00 | Alexandr Binda v Ivan Denisov | 6-2,6-7,10-7 |