| UTR Pro Tennis Series Zadar | 2021/07/04 10:00 | Matija Pecotic v Deni Zmak | 6-3,6-3 |
| UTR Pro Tennis Series Zadar | 2021/07/03 08:30 | Josip Krstanovic v Deni Zmak | 5-7,3-5 |
| UTR Pro Tennis Series Zadar | 2021/07/02 08:00 | Deni Zmak v Bozo Barun | 6-2,6-2 |
| UTR Pro Tennis Series Zadar | 2021/07/01 12:30 | Deni Zmak v Vito Tonejc | 6-3,5-2 |
| UTR Pro Tennis Series Zadar | 2021/06/30 11:00 | Arthus De La Bassetiere v Deni Zmak | 2-6,3-5 |
| UTR Pro Tennis Series Zadar | 2021/06/29 08:00 | Ihor Dudun v Deni Zmak | 3-6,2-6 |
| ITF M15 Rovinj | 2021/03/16 08:55 | Matteo Arnaldi v Deni Zmak | 6-3,6-4 |
| ITF M15 Rovinj | 2021/03/15 11:30 | Deni Zmak v Alen Rogic-Hadzalic | 6-3,7-6 |