| UTR Pro Tennis Series - Zadar | 2021/11/18 12:00 | Deni Zmak v Alexander Lazov | 6-3,6-7,5-3 |
| UTR Pro Tennis Series - Zadar | 2021/11/16 13:00 | Deni Zmak v Graham Maassen | 4-6,6-1,6-2 |
| UTR Pro Tennis Series - Zadar | 2021/11/15 09:00 | Jose A R Rodriguez v Deni Zmak | 1-6,1-5 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/23 08:30 | Simon Friis Soendergaard v Deni Zmak | 5-7,1-6 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/21 07:00 | Deni Zmak v Albert P Hansen | 6-1,6-1 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/20 08:30 | Deni Zmak v Jose Antonio Rodriguez Rodriguez | 6-1,5-2 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/19 07:00 | Deni Zmak v Arslan Temirhanov | 7-5,6-4 |
| UTR Pro Tennis Series - Copenhaga | 2021/10/18 11:30 | Deni Zmak v Maxim Landa | 6-0,5-1 |
| UTR Pro Tennis Series - Zadar | 2021/11/18 10:30 | Christos Keisidis v Alexander Chepik | 6-3,6-2 |
| UTR Pro Tennis Series - Zadar | 2021/11/16 09:00 | Christos Keisidis v Denis Parshutin | 6-3,6-7,6-3 |
| UTR Pro Tennis Series - Zadar | 2021/11/15 12:00 | Olexiy Kolisnyk v Christos Keisidis | 7-5,3-6,4-6 |
| UTR Pro Tennis Series - Nis | 2021/10/10 08:00 | Christos Keisidis v Vladimir Popov | 6-1,5-2 |
| UTR Pro Tennis Series - Nis | 2021/10/09 11:00 | Christos Keisidis v Lawrence Bataljin | 6-4,6-2 |
| UTR Pro Tennis Series - Nis | 2021/10/08 15:45 | Dusan Trunic v Christos Keisidis | 2-6,2-5 |
| UTR Pro Tennis Series - Nis | 2021/10/07 08:30 | George Botezan v Christos Keisidis | 6-3,6-3 |
| UTR Pro Tennis Series - Nis | 2021/10/05 14:00 | Aleksa Mardjonovic v Christos Keisidis | 2-6,7-5,6-4 |