| UTR Pro Tennis Series Zadar | 2021/07/04 08:30 | Jerko Brkic v Kajin, Karlo | 6-4,6-4 |
| UTR Pro Tennis Series Zadar | 2021/07/03 11:30 | Ihor Dudun v Kajin, Karlo | 3-6,1-6 |
| UTR Pro Tennis Series Zadar | 2021/07/01 11:00 | Kajin, Karlo v Matija Pecotic | 1-6,2-5 |
| UTR Pro Tennis Series Zadar | 2021/06/30 09:30 | Kajin, Karlo v Kiefer, Alexander | 3-6,1-6 |
| UTR Pro Tennis Series Zadar | 2021/06/29 12:30 | Kajin, Karlo v Khomich, Aleksei | 6-4,3-6,2-6 |
| UTR ProTennis Series Zadar | 2021/06/28 08:00 | Kajin, Karlo v Goetz, Ryan | 1-6,1-5 |
| ITF Croatia F3 | 2018/03/19 12:30 | Gabrieli, Tommaso v Kajin, Karlo | 7-6,6-4 |
| ITF Croatia F3 | 2018/03/18 10:30 | de Rosa, Marco v Kajin, Karlo | 6-7,6-2,2-6 |
| ITF M15 Warmbad-Villach | 2022/05/18 11:05 | Maximilian Homberg v Hubner, Edward | 6-4,5-7,2-6 |
| ITF - M25 Santa Margherita | 2022/05/10 10:00 | Maximilian Homberg v Marco Dessi | 4-6,4-6 |
| ITF - M15 Antalya | 2022/04/10 06:00 | Maximilian Homberg v Abibsi, Mohamed Ali | 6-1,4-6,5-10 |
| ITF - M15 Antalya | 2022/03/27 07:00 | Samuil Konov v Maximilian Homberg | 6-3,6-1 |
| ITF - M15 Antalya | 2022/03/21 07:00 | Abibsi, Mohamed Ali v Maximilian Homberg | 6-3,7-5 |
| ITF - M15 Antalya | 2022/03/20 07:00 | Stevan Popovic v Maximilian Homberg | 2-6,2-6 |
| ITF M15 Allershausen | 2021/09/02 11:45 | Maximilian Homberg v Veldheer, Mick | 3-6,2-6 |
| ITF M15 Allershausen | 2021/09/01 14:05 | Maximilian Homberg v Oliver Olsson | 6-4,6-3 |