| UTR Pro Tennis Series Zadar | 2021/06/30 08:00 | Krstanovic, Josip v Jerko Brkic | 6-4,5-3 |
| UTR Pro Tennis Series Zadar | 2021/06/29 11:00 | Krstanovic, Josip v de La Bassetiere, Constant | 1-6,6-3,6-6 |
| UTR Pro Tennis Series Zadar | 2021/06/28 12:30 | Sinius, Warren v Krstanovic, Josip | 2-6,1-5 |
| Sibenik, Singles M-ITF-CRO-05A | 2021/04/19 10:00 | Sadaoui, Mehdi v Krstanovic, Josip | 7-6,6-4 |
| Sibenik, Singles M-ITF-CRO-05A | 2021/04/18 10:00 | Krstanovic, Josip v Daljev, Pavle | 6-4,6-3 |
| ITF - M15 Opatija | 2021/03/21 11:00 | Oleksandr Ovcharenko v Krstanovic, Josip | 6-4,6-0 |
| ITF - M15 Rovinj | 2021/03/15 11:00 | Krstanovic, Josip v Federico Arnaboldi | 1-6,2-6 |
| ITF - M15 Rovinj | 2021/03/14 08:30 | Krstanovic, Josip v Frinzi, Mattia | 6-2,7-6 |
| UTR Pro Tennis Series Zadar | 2021/07/01 09:30 | de La Bassetiere, Constant v Nincevic, Frane | 3-6,2-6 |
| UTR Pro Tennis Series Zadar | 2021/06/29 11:00 | Sinius, Warren v Nincevic, Frane | 5-7,3-6 |
| UTR Pro Tennis Series Zadar | 2021/06/28 12:30 | Nincevic, Frane v Jerko Brkic | 6-1,7-5 |
| Sarajevo, Singles Main, M-ITF-BIH-05A | 2021/06/02 09:00 | Nincevic, Frane v Perchicot, Mathieu | 6-2,2-6,4-6 |
| Sibenik, Singles M-ITF-CRO-05A | 2021/05/17 08:00 | Nikola Basic v Nincevic, Frane | 6-7,6-1,10-8 |
| Challenger Zagreb | 2021/05/09 08:30 | Nincevic, Frane v Ramkumar Ramanathan | 4-6,3-6 |
| Sibenik, Singles M-ITF-CRO-05A | 2021/04/21 08:00 | Prechtel, Sebastian v Nincevic, Frane | 6-0,6-3 |
| Challenger Split Qual | 2021/04/11 12:25 | Nincevic, Frane v Tristan Lamasine | 1-6,5-7 |