| UTR Pro Tennis Series - Copenhaga | 2021/10/18 11:30 | Nikolaj Katic v Henrik Heise Korsgaard | 1-6,6-3,6-4 |
| ITF - M15 Doha | 2021/10/11 13:30 | Boris Butulija v Nikolaj Katic | 6-1,6-3 |
| ITF - M15 Doha - Calificari | 2021/10/10 15:45 | Theertha Shashank Macherla v Nikolaj Katic | 4-6,6-7 |
| ITF - M15 Doha | 2021/10/04 12:00 | Nikolaj Katic v Tao Mu | 0-6,1-6 |
| ITF - M15 Doha | 2021/10/03 13:20 | Alexey Dubinin v Nikolaj Katic | 2-6,1-6 |
| ITF - M25 Falun | 2021/09/26 11:00 | Nikolaj Katic v Daniel Little | 6-7,4-6 |
| ITF - M25 Jonkoping | 2021/09/19 11:00 | Ben Jones v Nikolaj Katic | 6-2,6-7,10-6 |
| UTR Pro Tennis Series - Ricany | 2021/09/08 09:00 | Nikolaj Katic v Jiri Barnat | 1-6,0-2 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/18 07:00 | Yurii Dzhavakian v Felipe Mikkelsen | 6-0,6-1 |
| UTR Pro Tennis Series - Mulheim | 2021/10/17 07:00 | Yurii Dzhavakian v Ivan Marrero Curbelo | 6-1,7-5 |
| UTR Pro Tennis Series - Mulheim | 2021/10/16 10:30 | Yurii Dzhavakian v Finn Bischof | 6-1,6-4 |
| UTR Pro Tennis Series - Mulheim | 2021/10/15 08:30 | Yurii Dzhavakian v Tim Sandkaulen | 0-0 |
| UTR Pro Tennis Series - Mulheim | 2021/10/14 10:00 | Yurii Dzhavakian v Constantin Schmitz | 4-6,5-7 |
| UTR Pro Tennis Series - Mulheim | 2021/10/13 10:00 | Edison Ambarzumjan v Yurii Dzhavakian | 3-6,4-6 |
| UTR Pro Tennis Series - Mulheim | 2021/10/12 08:30 | Jing L Weng v Yurii Dzhavakian | 5-7,6-1,6-3 |
| UTR Pro Tennis Series - Ricany | 2021/09/18 10:30 | Yurii Dzhavakian v Dominik Suc | 4-6,4-6 |