| UTR Pro Tennis Series Mulheim | 2021/09/25 10:30 | Christos Keisidis v Lawrence Bataljin | 6-4,5-3 |
| UTR Pro Tennis Series Nis | 2021/10/08 15:45 | Dusan Trunic v Christos Keisidis | 2-6,2-5 |
| UTR Pro Tennis Series Nis | 2021/10/07 08:30 | George Botezan v Christos Keisidis | 6-3,6-3 |
| UTR Pro Tennis Series Nis | 2021/10/05 14:00 | Aleksa Mardjonovic v Christos Keisidis | 2-6,7-5,6-4 |
| UTR Pro Tennis Series Nis | 2021/10/04 11:30 | Christos Keisidis v Alexander Lazov | 6-3,0-6,3-6 |
| UTR Pro Tennis Series Zadar | 2021/10/03 09:30 | Admir Kalender v Christos Keisidis | 6-2,6-0 |
| 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 Nis | 2021/10/08 16:45 | Lawrence Bataljin v Oleksandr Bielinskyi | 7-5,5-7,0-5 |
| UTR Pro Tennis Series Nis | 2021/10/07 08:30 | Lawrence Bataljin v Veljko Krstic | 7-6,3-6,5-7 |
| UTR Pro Tennis Series Nis | 2021/10/06 08:30 | Ivan Liutarevich v Lawrence Bataljin | 7-5,6-3 |
| UTR Pro Tennis Series Nis | 2021/10/05 09:00 | Stefan Ivic v Lawrence Bataljin | 4-6,4-5 |
| UTR Pro Tennis Series Zadar | 2021/10/03 08:00 | Duje Kekez v Lawrence Bataljin | 6-1,5-1 |
| UTR Pro Tennis Series Zadar | 2021/10/02 13:00 | Lawrence Bataljin v Ivan Liutarevich | 6-4,6-3 |
| UTR Pro Tennis Series Zadar | 2021/10/01 14:30 | Mile Matic v Lawrence Bataljin | 4-6,0-6 |
| UTR Pro Tennis Series Zadar | 2021/09/30 14:00 | Petar Pjevcevic v Lawrence Bataljin | 6-1,6-5 |