Stadium: Court 6 Round: 25 Ground: Hardcourt outdoor
| ITF - M15 Sharm El Sheikh | 2021/10/14 10:35 | Gabriel Decamps v Deviatiarov, Marat | 6-4,5-7,6-0 |
| ITF - M15 Sharm El Sheikh | 2021/10/13 09:35 | Alexandros Skorilas v Deviatiarov, Marat | 3-6,0-6 |
| ITF M15 Ulcinj | 2021/09/15 10:00 | Deviatiarov, Marat v Franco Emanuel Egea | 3-6,3-6 |
| ITF M15 Ulcinj | 2021/09/09 08:30 | Deviatiarov, Marat v Oleksandr Ovcharenko | 1-6,1-6 |
| ITF M15 Ulcinj | 2021/09/08 08:00 | Deviatiarov, Marat v Saito, Takashi | 6-3,6-4 |
| UTR Pro Tennis Series Barcelona | 2021/08/15 08:00 | Andrey Chepelev v Deviatiarov, Marat | 6-1,6-7,2-6 |
| UTR Pro Tennis Series Barcelona | 2021/08/14 08:00 | Fermin Tenti v Deviatiarov, Marat | 0-6,1-6 |
| UTR Pro Tennis Series Barcelona | 2021/08/12 10:00 | Pujol Navarro, Bruno v Deviatiarov, Marat | 4-6,6-4,5-6 |
| ITF - M15 Sharm El Sheikh | 2021/10/13 08:00 | Mikula, Michal v Andrea Guerrieri | 7-6,7-6 |
| ITF M15 Bad Waltersdorf | 2021/09/01 08:00 | Andrea Guerrieri v Giorgio Tabacco | 4-6,4-6 |
| ITF M15 Warmbad-Villach | 2021/08/18 08:00 | Peter Heller v Andrea Guerrieri | 6-1,6-1 |
| ITF M15 Gdynia | 2021/08/09 08:00 | Andrea Guerrieri v Juliusz Bienkiewicz | 6-2,2-6,7-10 |
| ITF M15 Parnu | 2021/08/05 09:55 | Sabanin, Yan v Andrea Guerrieri | 6-2,6-3 |
| ITF M15 Parnu | 2021/08/04 16:00 | Andrea Guerrieri v Seeman, Johannes | 2-6,7-6,6-4 |
| ITF M15 Bergamo | 2021/06/21 12:00 | Andrea Guerrieri v Vilardo, Francesco | 6-7,6-2,10-12 |
| ITF M15 Genova | 2021/06/15 08:50 | Juan Bautista Otegui v Andrea Guerrieri | 6-3,6-1 |