| UTR Pro Tennis Series Sofia | 2021/09/01 11:00 | Mick Lescure v Vladimir Popov | 1-6,4-6 |
| UTR Pro Tennis Series Sofia | 2021/08/31 11:00 | Mihael Mihaylov v Vladimir Popov | 1-6,3-5 |
| UTR Pro Tennis Series Sofia | 2021/08/30 07:00 | Viktor Markov v Vladimir Popov | 6-3,7-6 |
| UTR Pro Tennis Series Pazardzhik | 2021/07/18 07:30 | Dmitrii Vasilev v Vladimir Popov | 2-6,1-5 |
| UTR Pro Tennis Series Pazardzhik | 2021/07/17 12:00 | Vladimir Popov v Arthus De La Bassetiere | 6-4,6-1 |
| UTR Pro Tennis Series Pazardzhik | 2021/07/15 09:00 | Vladimir Popov v Aleksandr Braynin | 4-6,5-7 |
| UTR Pro Tennis Series Pazardzhik | 2021/07/14 07:30 | Vladimir Popov v Gorazd Srbljak | 1-6,4-6 |
| UTR Pro Tennis Series Pazardzhik | 2021/07/13 10:30 | Vladimir Popov v Yanaki Milev | 4-6,6-4,2-6 |
| UTR Pro Tennis Series Sofia | 2021/09/01 08:00 | Christos Keisidis v Mario Radev | 6-1,4-6,6-4 |
| UTR Pro Tennis Series Sofia | 2021/08/31 08:00 | Christos Keisidis v Josh Sheehy | 4-6,4-6 |
| UTR Pro Tennis Series Sofia | 2021/08/30 07:00 | Christos Keisidis v Denislav Prodanov | 6-1,5-1 |
| ITF M15 Heraklion | 2021/06/09 08:00 | Antonio Cayetano March v Christos Keisidis | 4-6,7-6,6-2 |
| ITF M15 Heraklion | 2021/06/08 06:30 | Sean Hodkin v Christos Keisidis | 6-4,5-7,4-10 |
| ITF M15 Heraklion | 2021/06/07 09:00 | Christos Keisidis v Alexander Gaponenko | 6-4,6-1 |
| ITF M15 Heraklion | 2021/06/06 11:00 | Michel-Alexandre Fortin v Christos Keisidis | 0-6,0-6 |
| ITF M15 Heraklion | 2021/05/31 06:30 | Mattia Bellucci v Christos Keisidis | 6-4,6-3 |