| UTR Pro Tennis Series Zadar | 2021/11/16 12:00 | Robert Rumler v Duje Kekez | 2-6,4-6 |
| UTR Pro Tennis Series Zadar | 2021/11/15 12:00 | Robert Rumler v Valerii Naumenko | 6-0,6-0 |
| UTR Pro Tennis Series Portoroz | 2021/08/29 09:30 | Robert Rumler v Egor Agafonov | 7-6,6-1 |
| UTR Pro Tennis Series Portoroz | 2021/08/26 10:00 | Robert Rumler v Gal Emersic Potocnik | 6-2,6-1 |
| UTR Pro Tennis Series Portoroz | 2021/08/26 07:00 | Robert Rumler v Giacomo Revelli | 3-6,4-6 |
| UTR Pro Tennis Series Portoroz | 2021/08/25 07:00 | Robert Rumler v Paras Dahiya | 7-6,3-6,6-5 |
| ITF M25 Prostejov | 2021/08/17 07:55 | Robert Rumler v Nick Chappell | 0-6,4-6 |
| ITF M25 Grodzisk Mazowiecki | 2021/08/04 15:30 | Robert Rumler v Shintaro Mochizuki | 6-3,3-6,2-6 |
| UTR Pro Tennis Series Zadar | 2021/11/16 12:00 | Valerii Naumenko v Vladimir Popov | 3-6,3-6 |
| UTR Pro Tennis Series Zadar | 2021/11/14 12:00 | Vladimir Popov v Duje Kekez | 0-6,2-6 |
| UTR Pro Tennis Series Brasov | 2021/10/28 11:30 | Vasile Antonescu v Vladimir Popov | 4-4 |
| UTR Pro Tennis Series Brasov | 2021/10/27 07:00 | Edris Fetisleam v Vladimir Popov | 6-0,5-2 |
| UTR Pro Tennis Series Brasov | 2021/10/25 10:00 | Ioan Alexandru Chirita v Vladimir Popov | 6-2,6-2 |
| UTR Pro Tennis Series Nis | 2021/10/10 08:00 | Christos Keisidis v Vladimir Popov | 6-1,5-2 |
| UTR Pro Tennis Series Nis | 2021/10/09 13:15 | Aleksandar Ljubojevic v Vladimir Popov | 4-6,5-7 |
| UTR Pro Tennis Series Nis | 2021/10/08 18:15 | Petar Pjevcevic v Vladimir Popov | 2-6,6-0,5-1 |