Stadium: Court 6 Round: 26 Ground: Hardcourt indoor
| ITF M15 St Petersburg | 2021/04/14 10:40 | Vladimir Ivanov v Constantin Bittoun Kouzmine | 1-6,7-6,2-6 |
| ITF M15 St Petersburg | 2021/04/12 10:25 | Pavel Shchaya-Zubrov v Constantin Bittoun Kouzmine | 0-6,3-6 |
| ITF M15 St Petersburg | 2021/04/07 09:55 | Illya Beloborodko v Constantin Bittoun Kouzmine | 6-3,6-1 |
| ITF M15 St Petersburg | 2021/04/05 08:40 | Constantin Bittoun Kouzmine v Matic Spec | 6-7,6-7 |
| ITF M15 St Petersburg | 2021/04/04 11:55 | Jaimee Floyd Angele v Constantin Bittoun Kouzmine | 6-1,1-6,7-10 |
| ITF M15 Poitiers | 2021/03/14 11:45 | Constantin Bittoun Kouzmine v Vincent Stouff | 6-3,6-7,7-10 |
| ITF M15 Bratislava | 2021/03/10 10:30 | Constantin Bittoun Kouzmine v Vitaliy Sachko | 6-3,2-6,3-6 |
| ITF M15 Bratislava | 2021/03/09 09:00 | Martin Dobry v Constantin Bittoun Kouzmine | 3-6,0-6 |
| ITF M15 St Petersburg | 2021/04/14 09:55 | Egor Noskin v Alexey Zakharov | 2-6,6-1,2-6 |
| ITF M15 St Petersburg | 2021/04/08 10:45 | Sarp Agabigun v Alexey Zakharov | 6-2,6-4 |
| ITF M15 St Petersburg | 2021/04/07 07:00 | Naoki Tajima v Alexey Zakharov | 3-6,6-1,3-6 |
| ITF M15 Kazan | 2021/03/13 08:00 | Alexey Zakharov v Alibek Kachmazov | 7-5,6-3 |
| ITF M15 Kazan | 2021/03/12 09:05 | Alexey Zakharov v Alexandr Binda | 6-2,7-6 |
| ITF M15 Kazan | 2021/03/11 08:00 | Alexey Zakharov v Yaraslav Shyla | 6-3,6-2 |
| ITF M15 Kazan | 2021/03/09 12:15 | Alexey Zakharov v Igor Kudriashov | 4-6,6-2,6-3 |
| Challenger St. Petersburg | 2021/02/28 09:20 | Alessandro Bega v Alexey Zakharov | 6-4,6-2 |