Estádio: Court 6 Round: 62 Ground: Clay
| ITF - M15 Novi Sad | 2021/07/25 12:00 | Gabriel Donev v Besir Durguti | 6-1,6-1 |
| ITF - M15 Sófia | 2021/07/09 08:30 | Gabriel Donev v Alexander Weis | 6-4,3-6,6-7 |
| ITF - M15 Sófia | 2021/07/08 11:40 | Simeon Terziev v Gabriel Donev | 1-6,6-4,0-6 |
| ITF - M15 Sófia | 2021/07/07 08:50 | Mattia Frinzi v Gabriel Donev | 5-7,2-6 |
| ITF - M15 Novomoskovsk | 2021/06/03 11:45 | Alexander Zgirovsky v Gabriel Donev | 6-2,3-6,10-8 |
| ITF - M15 Novomoskovsk | 2021/05/31 06:15 | Gabriel Donev v Denis Parshutin | 6-0,6-4 |
| ITF - M15 Novomoskovsk | 2021/05/31 06:15 | Gabriel Donev v Roman Boychuk | 6-1,6-0 |
| ITF - M15 Novomoskovsk | 2021/05/26 09:05 | Ivan Nedelko v Gabriel Donev | 6-3,6-4 |
| ITF - M15 Novi Sad | 2021/07/25 08:15 | Biagio Gramaticopolo v Dusan Rajic | 4-6,4-6 |
| ITF - M15 Doboj | 2021/07/11 12:30 | Dusan Rajic v Dusan Obradovic | 4-6,3-6 |
| ITF - M25 Velenje | 2021/07/05 12:05 | Michele Vianello v Dusan Rajic | 6-4,6-2 |
| ITF - M25 Velenje | 2021/07/04 07:30 | Inaki Cabrera Bello v Dusan Rajic | 1-6,4-6 |
| ITF - M25 Belgrado | 2021/06/28 07:00 | Edoardo Lavagno v Dusan Rajic | 6-1,6-2 |
| ITF - M25 Belgrado | 2021/06/27 07:00 | Dusan Rajic v Ivan Mikhaylyuk | 2-6,6-0,12-10 |
| ITF - M15 Brcko | 2021/05/21 13:05 | Dusan Rajic v Eric Vanshelboim | 3-6,1-6 |
| ITF - M15 Brcko | 2021/05/21 07:35 | Kristjan Tamm v Dusan Rajic | 4-6,5-7 |