Stadium: Court 1 Round: 54 Ground: Hardcourt indoor
| 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 Ricany | 2021/09/07 13:00 | Nikolaj Katic v Maxence Broville | 3-6,3-6 |
| ITF M25 Muttenz | 2021/08/16 07:55 | Mischa Lanz v Nikolaj Katic | 7-5,6-4 |
| ITF M15 Frederiksberg | 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 M25 Jonkoping | 2021/09/22 09:30 | Daniel Little v Filip Bergevi | 6-7,6-2,5-7 |
| ITF M25 Jonkoping | 2021/09/21 07:30 | Daniel Little v Patrik Niklas-Salminen | 6-4,7-6 |
| ITF M25 Jonkoping | 2021/09/20 09:20 | Daniel Little v Jonathan Stenberg | 6-4,6-2 |
| ITF M25 Sintra | 2021/09/15 14:40 | Daniel Little v John Echeverria | 6-3,4-6,3-6 |
| ITF M25 Sintra | 2021/09/14 13:20 | Daniel Little v Alan F R Fierros | 4-6,6-7 |
| ITF M25 Sintra | 2021/09/13 12:00 | Daniel Little v Iago D Alvarez | 6-1,6-3 |
| ITF M25 Sintra | 2021/09/08 09:00 | Anton Matusevich v Daniel Little | 6-4,6-4 |
| ITF M25 Sintra | 2021/09/07 08:30 | Diego F Flores v Daniel Little | 6-4,0-6,6-10 |