Stadium: Court 4 Round: 25 Ground: Clay
| ITF M15 Telavi | 2021/08/02 10:15 | Borisiouk, Martin v Boborykin, Alexander | 6-0,3-6,10-6 |
| ITF M15 Telavi | 2021/08/02 06:00 | Borisiouk, Martin v Mikhail Malakhovich | 6-2,6-0 |
| ITF M25 Telavi | 2021/07/26 13:55 | Borisiouk, Martin v Yeshaya, Omer | 3-6,6-4,10-12 |
| ITF M25 Nur-Sultan | 2021/07/08 05:00 | Yu Hsiou Hsu v Borisiouk, Martin | 6-0,2-6,6-3 |
| ITF M25 Nur-Sultan | 2021/07/07 04:00 | Borisiouk, Martin v Nabiev, Olimjon | 6-2,6-0 |
| ITF M25 Nur-Sultan | 2021/07/06 08:10 | Borisiouk, Martin v Mukhtarulin, Timur | 6-1,6-3 |
| ITF M15 St Petersburg | 2021/04/12 07:00 | Alafia Ayeni v Borisiouk, Martin | 6-4,1-6,10-8 |
| ITF M15 St Petersburg Qual | 2021/04/11 08:40 | Bolotov, Sergey v Borisiouk, Martin | 5-7,2-6 |
| ITF M15 Novi Sad | 2021/07/30 08:00 | Gabriel Donev v Juan Pablo Paz | 4-6,5-7 |
| ITF M15 Novi Sad | 2021/07/29 09:25 | Gabriel Donev v Gorazd Srbljak | 6-2,6-4 |
| ITF M15 Novi Sad | 2021/07/28 11:10 | Nedelko, Ivan v Gabriel Donev | 4-6,1-6 |
| ITF M15 Novi Sad | 2021/07/26 09:00 | Gabriel Donev v Rajic, Dusan | 6-2,6-2 |
| ITF M15 Novi Sad | 2021/07/25 12:00 | Gabriel Donev v Durguti, Besir | 6-1,6-1 |
| ITF M15 Sofia | 2021/07/09 08:30 | Gabriel Donev v Alexander Weis | 6-4,3-6,6-7 |
| ITF M15 Sofia | 2021/07/08 11:40 | Terziev, Simeon v Gabriel Donev | 1-6,6-4,0-6 |
| ITF M15 Sofia | 2021/07/07 08:50 | Frinzi, Mattia v Gabriel Donev | 5-7,2-6 |