| UTR Pro Tennis Series Zadar | 2021/10/02 08:30 | Admir Kalender v Petar Pjevcevic | 6-3,6-1 |
| UTR Pro Tennis Series Zadar | 2021/10/01 11:00 | Admir Kalender v Jose A R Rodriguez | 6-4,6-3 |
| UTR Pro Tennis Series Zadar | 2021/09/30 08:00 | Admir Kalender v Alen Rogic-Hadzalic | 2-6,6-4,5-6 |
| UTR Pro Tennis Series Zadar | 2021/09/29 12:00 | Borna Devald v Admir Kalender | 5-7,6-2,1-5 |
| UTR Pro Tennis Series Zadar | 2021/09/28 08:00 | Myroslav Bondar v Admir Kalender | 2-6,2-6 |
| ITF M15 Ulcinj | 2021/09/12 09:30 | Alexandre Aubriot v Admir Kalender | 6-1,6-3 |
| ITF M15 Bad Waltersdorf | 2021/08/25 08:50 | Lukas Krainer v Admir Kalender | 6-4,3-6,6-2 |
| ITF M15 Bad Waltersdorf | 2021/08/23 13:00 | Admir Kalender v Fletcher Scott | 6-4,6-2 |
| UTR Pro Tennis Series Zadar | 2021/10/02 11:30 | Christos Keisidis v Ivan Denisov | 3-6,6-1,6-5 |
| UTR Pro Tennis Series Zadar | 2021/10/01 08:00 | Christos Keisidis v Drazen Petrovic | 6-4,6-4 |
| UTR Pro Tennis Series Zadar | 2021/09/30 09:30 | Christos Keisidis v Stefanos Sakellaridis | 4-6,6-4,6-4 |
| UTR Pro Tennis Series Zadar | 2021/09/29 08:00 | Duje Kekez v Christos Keisidis | 6-2,2-6,5-6 |
| UTR Pro Tennis Series Zadar | 2021/09/28 12:30 | Janos Fekete v Christos Keisidis | 6-4,5-3 |
| UTR Pro Tennis Series Mulheim | 2021/09/25 10:30 | Christos Keisidis v Lawrence Bataljin | 6-4,5-3 |
| UTR Pro Tennis Series Mulheim | 2021/09/24 08:00 | Christos Keisidis v Jurriaan Bol | 1-6,4-6 |
| UTR Pro Tennis Series Mulheim | 2021/09/23 11:00 | Christos Keisidis v Artem Podorozhnyi | 5-7,2-5 |