| UTR Pro Tennis Series Sofia | 2021/08/30 10:00 | Ioan Alexandru Chirita v Simeon Terziev | 4-6,6-3,3-6 |
| ITF M25 Pitesti | 2021/08/04 05:55 | Corentin Denolly v Simeon Terziev | 6-3,7-5 |
| ITF M25 Pitesti | 2021/08/03 05:55 | Toby Martin v Simeon Terziev | 5-7,4-6 |
| ITF M15 Sofia | 2021/07/08 11:40 | Simeon Terziev v Gabriel Donev | 1-6,6-4,0-6 |
| ITF M15 Sofia | 2021/07/07 08:35 | Dan Added v Simeon Terziev | 7-5,5-7,4-6 |
| ITF M15 Antalya | 2021/06/30 10:30 | Simeon Terziev v Carlos Sanchez Jover | 6-2,0-6,6-7 |
| ITF M15 Antalya | 2021/06/21 07:00 | Stefan Palosi v Simeon Terziev | 6-0,7-5 |
| ITF M15 Antalya | 2021/06/20 07:00 | Simeon Terziev v Gabriel Roveri Sidney | 4-6,7-6,10-8 |
| UTR Pro Tennis Series Sofia | 2021/08/30 08:30 | Veselin Kiselkov v Adriano Dzhenev | 3-6,6-1,4-5 |