| UTR Pro Tennis Series Ricany | 2021/09/07 13:00 | Nikolaj Katic v Maxence Broville | 3-6,3-6 |
| ITF - Muttenz M25 | 2021/08/16 07:55 | Mischa Lanz v Nikolaj Katic | 7-5,6-4 |
| ITF - Frederiksberg M15 | 2021/08/01 08:00 | Adam Heinonen v Nikolaj Katic | 6-3,6-7,10-6 |
| UTR Pro Tennis Series Copenhagen | 2021/06/19 07:00 | Nikolaj Katic v Warren Sinius | 4-5 |
| UTR Pro Tennis Series Copenhagen | 2021/06/18 11:00 | Benjamin Hannestad v Nikolaj Katic | 6-4,6-1 |
| UTR Pro Tennis Series Copenhagen | 2021/06/17 08:00 | Daniel De Jonge v Nikolaj Katic | 4-6,6-4,6-0 |
| ITF Turkey F3 | 2018/01/20 09:00 | Nikolaj Katic v Roberts Grinvalds | 0-6,4-6 |
| ITF Turkey F1 | 2018/01/07 08:30 | Zizou Bergs v Nikolaj Katic | 6-2,6-1 |
| UTR Pro Tennis Series Ricany | 2021/09/06 09:00 | Krystof Zapsky v Jiri Barnat | 0-6,3-6 |
| ITF - Ricany M25 | 2021/09/01 09:20 | Jiri Barnat v Martin Krumich | 2-6,3-6 |
| ITF - Bratysława M15 | 2021/08/25 08:00 | Palaphoom Kovapitukted v Jiri Barnat | 6-3,6-7,6-1 |
| ITF - Bratysława M15 | 2021/08/24 08:00 | Jiri Barnat v Jakub Kroslak | 6-3,7-5 |
| ITF - Bratysława M15 | 2021/08/23 09:00 | Jiri Barnat v Radovan Michalik | 7-5,6-0 |
| ITF - Bratysława M15 | 2021/08/18 09:30 | Jiri Barnat v Fabian Marozsan | 4-6,2-6 |
| ITF - Bratysława M15 | 2021/08/17 08:00 | Eric Morris v Jiri Barnat | 4-6,6-7 |
| ITF - Praga M25 | 2021/05/10 09:00 | Adam Pavlasek v Jiri Barnat | 6-3,4-6,14-12 |