Stadium: Court 2 Round: 44 Ground: Clay
| ITF M15 Novi Sad | 2021/07/25 07:00 | Martin Zeljenka v Danilo Raicevic | 4-6,4-6 |
| ITF M25 Kottingbrunn | 2021/07/19 12:25 | Peter Goldsteiner v Martin Zeljenka | 6-4,7-6 |
| ITF M25 Kottingbrunn | 2021/07/18 07:30 | Martin Zeljenka v Rafael Kis Balazs | 2-6,6-4,10-2 |
| ITF M25 Belgrade | 2021/06/29 07:00 | Bogdan Pavel v Martin Zeljenka | 6-1,6-3 |
| ITF M25 Belgrade | 2021/06/28 10:00 | Martin Zeljenka v Matvey Minin | 7-5,6-3 |
| ITF M25 Belgrade | 2021/06/27 12:00 | Martin Zeljenka v George Gregoriou | 6-1,6-1 |
| ITF M15 Sibenik | 2021/05/17 11:00 | Martin Zeljenka v Martin Breysach | 6-7,3-6 |
| ITF M15 Sibenik | 2021/05/16 07:30 | Joris Hoogland v Martin Zeljenka | 6-7,3-6 |
| ITF M15 Antalya | 2021/06/28 12:20 | Daniil Glinka v Samuil Konov | 6-3,6-1 |
| ITF M15 Antalya | 2021/06/27 06:30 | Sabit Suntic v Samuil Konov | 4-6,3-6 |
| UTR Pro Tennis Series Bucharest | 2021/06/03 12:00 | Kuzey Cekirge v Samuil Konov | 6-3,4-6,7-5 |
| UTR Pro Tennis Series Bucharest | 2021/06/03 06:00 | Vlad Andrei Dancu v Samuil Konov | 6-3,5-7,6-2 |
| UTR Pro Tennis Series Bucharest | 2021/06/02 13:00 | Valentin Vanta v Samuil Konov | 4-6,6-2,6-2 |
| ITF M15 Bucharest | 2021/05/24 08:00 | Samuil Konov v Taiyo Yamanaka | 4-6,0-6 |
| ITF M15 Antalya | 2021/03/21 07:00 | Samuil Konov v Vladislav Gorbatenko | 3-6,2-6 |
| ITF M15 Antalya | 2021/03/14 07:00 | Federico Bertuccioli v Samuil Konov | 6-3,6-3 |