Stadium: Court 4 Round: 28 Ground: Hardcourt indoor
| ITF M15 St Petersburg | 2021/04/09 08:00 | Cozbinov, Alexander v Dubrivnyy, Artem | 6-4,6-7,6-3 |
| ITF M15 St Petersburg | 2021/04/08 09:00 | Tyurnev, Evgeny v Cozbinov, Alexander | 6-2,3-6,2-6 |
| ITF M15 St Petersburg | 2021/04/07 08:30 | Cozbinov, Alexander v Boris Pokotilov | 6-0,6-0 |
| ITF - M15 Antalya | 2021/03/30 10:00 | Fayziev, Sanjar v Cozbinov, Alexander | 6-4,6-3 |
| ITF - M15 Antalya | 2021/03/21 07:00 | Cozbinov, Alexander v Taiyo Yamanaka | 3-6,3-6 |
| ITF - M15 Antalya | 2021/03/18 07:00 | Matheus P De Almeida v Cozbinov, Alexander | 6-2,6-4 |
| ITF - M15 Antalya | 2021/03/17 10:00 | Cozbinov, Alexander v Vanneste, Jeroen | 6-0,6-3 |
| ITF M15 Kazan | 2021/03/10 15:10 | Yanki Erel v Cozbinov, Alexander | 6-3,6-4 |
| ITF M15 St Petersburg | 2021/04/09 08:00 | Nedelko, Ivan v Sarp Agabigun | 6-1,6-4 |
| ITF M15 St Petersburg | 2021/04/08 07:00 | Nedelko, Ivan v Simon Freund | 6-2,6-4 |
| ITF M15 St Petersburg | 2021/04/06 09:00 | Nedelko, Ivan v Petr Bar Biryukov | 6-3,6-1 |
| ITF M15 St Petersburg | 2021/04/05 08:35 | Nedelko, Ivan v Borisiouk, Martin | 6-2,6-1 |
| ITF M15 St Petersburg | 2021/04/04 13:20 | Nedelko, Ivan v Sergei Pogosian | 6-1,6-1 |
| Challenger - Oeiras | 2021/03/28 10:00 | Cabral, Francisco v Nedelko, Ivan | 6-2,5-7,6-4 |
| Challenger - Zadar | 2021/03/25 09:30 | Nikola Milojevic v Nedelko, Ivan | 6-2,6-1 |
| Challenger - Zadar | 2021/03/23 13:30 | Gabashvili, Teimuraz v Nedelko, Ivan | 2-6,6-2,3-6 |