| UTR Pro Tennis Series Zadar | 2021/07/02 12:30 | Josip Krstanovic v Frane Nincevic | 6-4,1-6,7-5 |
| UTR Pro Tennis Series Zadar | 2021/06/30 08:00 | Josip Krstanovic v Jerko Brkic | 6-4,5-3 |
| UTR Pro Tennis Series Zadar | 2021/06/29 11:00 | Josip Krstanovic v Constant De La Bassetiere | 1-6,6-3,6-6 |
| UTR Pro Tennis Series Zadar | 2021/06/28 12:30 | Warren Sinius v Josip Krstanovic | 2-6,1-5 |
| ITF M15 Sibenik | 2021/04/19 10:00 | Mehdi Sadaoui v Josip Krstanovic | 7-6,6-4 |
| ITF M15 Sibenik | 2021/04/18 10:00 | Josip Krstanovic v Pavle Daljev | 6-4,6-3 |
| ITF M15 Opatija | 2021/03/21 11:00 | Oleksandr Ovcharenko v Josip Krstanovic | 6-4,6-0 |
| ITF M15 Rovigno | 2021/03/15 11:00 | Josip Krstanovic v Federico Arnaboldi | 1-6,2-6 |
| 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 Rovigno | 2021/03/16 08:55 | Matteo Arnaldi v Deni Zmak | 6-3,6-4 |
| ITF M15 Rovigno | 2021/03/15 11:30 | Deni Zmak v Alen Rogic-Hadzalic | 6-3,7-6 |
| ITF M15 Rovigno | 2021/03/14 08:30 | Deni Zmak v Alessandro Ragazzi | 6-3,7-6 |
| Adriatic Tennis Series | 2020/06/16 10:00 | Danilo Petrovic v Deni Zmak | 6-2,6-4 |