Stadium: Court 4 Round: 28 Ground: Hardcourt indoor
| ITF M15 St Petersburg | 2021/04/16 07:55 | Matic Spec v Alexey Zakharov | 6-2,6-4 |
| ITF M15 St Petersburg | 2021/04/15 07:00 | Jakub Paul v Matic Spec | 6-7,6-4,3-6 |
| ITF M15 St Petersburg | 2021/04/14 09:15 | Matic Spec v Alafia Ayeni | 6-3,6-4 |
| ITF M15 St Petersburg | 2021/04/12 10:15 | Matic Spec v Daniel Ibragimov | 6-1,6-1 |
| ITF M15 St Petersburg Qual | 2021/04/11 07:00 | Matic Spec v Maksim Starostin | 6-3,6-2 |
| ITF M15 St Petersburg | 2021/04/08 09:00 | Matic Spec v Aristarkh Safonov | 3-6,5-7 |
| ITF M15 St Petersburg | 2021/04/07 07:00 | Savriyan Danilov v Matic Spec | 3-6,2-6 |
| ITF M15 St Petersburg | 2021/04/05 08:40 | Constantin Bittoun Kouzmine v Matic Spec | 6-7,6-7 |
| ITF M15 St Petersburg | 2021/04/16 09:30 | Yanki Erel v Sarp Agabigun | 6-4,6-1 |
| ITF M15 St Petersburg | 2021/04/15 12:00 | Patrik Rikl v Yanki Erel | 3-6,5-7 |
| ITF M15 St Petersburg | 2021/04/14 07:00 | Yanki Erel v Alexander Cozbinov | 7-6,7-6 |
| ITF M15 St Petersburg | 2021/04/09 10:50 | Illya Beloborodko v Yanki Erel | 7-6,2-6,6-3 |
| ITF M15 St Petersburg | 2021/04/08 11:15 | Yanki Erel v Konstantin Kravchuk | 6-4,6-1 |
| ITF M15 St Petersburg | 2021/04/07 07:00 | Ivan Davydov v Yanki Erel | 2-6,3-6 |
| ITF M15 St Petersburg | 2021/04/05 06:55 | Yanki Erel v Dominik Recek | 7-5,6-2 |
| ITF M15 St Petersburg | 2021/04/04 08:25 | Yanki Erel v Mert Alkaya | 6-1,7-5 |