Stadium: Court 2 Round: 62 Ground: Hardcourt outdoor
| ITF M15 Torello | 2021/10/31 11:00 | Stefanos Sakellaridis v Sandro Szic | 6-1,6-3 |
| ITF M15 Madrid | 2021/10/28 09:30 | Lucas Bouquet v Stefanos Sakellaridis | 6-4,6-2 |
| ITF M15 Madrid | 2021/10/27 08:00 | Jaime Caldes v Stefanos Sakellaridis | 3-6,1-6 |
| ITF M25 Madrid | 2021/10/26 08:00 | Stefan Micov v Stefanos Sakellaridis | 4-6,6-7 |
| ITF M15 Girona | 2021/10/17 13:00 | Stefanos Sakellaridis v Giuseppe Tresca | 6-2,1-6,7-10 |
| UTR Pro Tennis Series Zadar | 2021/10/03 08:00 | Stefanos Sakellaridis v Mile Matic | 5-7,4-5 |
| UTR Pro Tennis Series Zadar | 2021/10/02 11:30 | Stefanos Sakellaridis v Myroslav Bondar | 6-2,5-0 |
| UTR Pro Tennis Series Zadar | 2021/10/01 08:00 | Janos Fekete v Stefanos Sakellaridis | 6-1,6-6 |
| ITF M25 Madrid | 2021/09/14 09:05 | Nikolas Sanchez Izquierdo v Constantinos Koshis | 6-2,6-2 |
| ITF M25 Madrid | 2021/09/13 09:00 | Hermanni Tiainen v Constantinos Koshis | 4-6,4-6 |
| ITF M15 Sharm El Sheikh | 2021/02/02 07:30 | Aidan Mchugh v Constantinos Koshis | 6-2,6-4 |
| ITF M15 Sharm El Sheikh | 2021/02/01 10:30 | Constantinos Koshis v Robert Strombachs | 3-6,6-2,10-6 |
| ITF M15 Sharm El Sheikh | 2021/01/31 07:00 | Lucas Hellfritsch v Constantinos Koshis | 2-6,5-7 |
| ITF M15 Antalya | 2021/01/13 09:45 | Constantinos Koshis v Federico Arnaboldi | 1-6,2-6 |
| ITF M15 Antalya | 2021/01/12 07:00 | Constantinos Koshis v Igor Trunov | 6-2,6-4 |
| ITF M15 Antalya | 2021/01/11 07:00 | Billy Harris v Constantinos Koshis | 7-6,6-7,6-10 |