Stadium: Center Court Round: 19 Ground: Clay
| Challenger Warsaw | 2021/08/22 13:35 | Johan Nikles v Lucas Gerch | 6-4,7-5 |
| ATP Gstaad | 2021/07/19 10:30 | Johan Nikles v Vit Kopriva | 2-6,1-6 |
| Challenger Amersfoort | 2021/07/15 18:05 | Johan Nikles v Lukas Rosol | 2-6,1-6 |
| Challenger Amersfoort | 2021/07/13 10:15 | Ryan Nijboer v Johan Nikles | 6-7,2-6 |
| Challenger Amersfoort | 2021/07/12 09:00 | Jeremy Jahn v Johan Nikles | 2-6,3-6 |
| Challenger Amersfoort | 2021/07/11 14:00 | Dominik Palan v Johan Nikles | 4-6,6-7 |
| ITF M25 The Hague | 2021/07/03 08:00 | Javier Barranco Cosano v Johan Nikles | 7-5,6-4 |
| ITF M25 The Hague | 2021/07/02 10:30 | Mateus Alves v Johan Nikles | 2-6,6-7 |
| Challenger Warsaw | 2021/08/22 12:15 | Jonathan Mridha v David Poljak | 2-6,6-4,6-2 |
| ITF M15 Bratislava | 2021/08/19 08:00 | Jonathan Mridha v Peter Fajta | 6-7,5-7 |
| ITF M15 Bratislava | 2021/08/17 10:30 | Jonathan Mridha v Peter Benjamin Privara | 6-3,6-3 |
| ITF M15 Frederiksberg | 2021/08/08 10:00 | Markus Eriksson v Jonathan Mridha | 3-6,6-7 |
| ITF M15 Frederiksberg | 2021/08/07 12:00 | Jonathan Mridha v Benjamin Hannestad | 0-6,6-2,6-4 |
| ITF M15 Frederiksberg | 2021/08/06 09:00 | Jonathan Mridha v Christian Sigsgaard | 6-4,6-4 |
| ITF M15 Frederiksberg | 2021/08/05 13:00 | Jonathan Mridha v Oscar Moraing | 6-1,6-3 |
| ITF M15 Frederiksberg | 2021/08/04 12:05 | Jonathan Mridha v Adrian Oetzbach | 6-2,6-3 |