| UTR Pro Tennis Series Zadar | 2021/06/29 12:30 | Karlo Kajin v Aleksei Khomich | 6-4,3-6,2-6 |
| UTR Pro Tennis Series Zadar | 2021/06/28 08:00 | Karlo Kajin v Ryan Goetz | 1-6,1-5 |
| ITF Croacia F3 | 2018/03/19 12:30 | Tommaso Gabrieli v Karlo Kajin | 7-6,6-4 |
| ITF Croacia F3 | 2018/03/18 10:30 | Marco De Rosa v Karlo Kajin | 6-7,6-2,2-6 |
| ITF Croacia F2 | 2018/03/12 08:00 | Andres Gabriel Ciurletti v Karlo Kajin | 6-3,6-3 |
| ITF Croacia F2 | 2018/03/10 09:00 | Karlo Kajin v Justin Schlageter | 3-6,6-2,6-4 |
| ITF Croacia F1 | 2018/03/08 09:00 | Pascal Meis v Karlo Kajin | 6-3,6-1 |
| ITF Austria F5 | 2017/07/29 07:00 | Charles Broom v Karlo Kajin | 6-0,6-4 |
| UTR Pro Tennis Series Zadar | 2021/06/29 14:00 | Ryan Goetz v Alexander Kiefer | 6-0,6-2 |