Stadium: MTA 08 Round: 62 Ground: Clay
| ITF - M15 Antalya | 2021/04/11 07:00 | Matthew Dellavedova v Oh, Seong-Gook | 7-5,5-7,10-8 |
| ITF - M15 Antalya | 2021/04/05 07:00 | Reinberg, Emil v Oh, Seong-Gook | 6-2,6-2 |
| ITF - M15 Antalya | 2021/04/04 06:30 | Stefanos Sakellaridis v Oh, Seong-Gook | 2-6,4-6 |
| ITF - M15 Antalya | 2021/03/29 07:00 | Manuel Mazza v Oh, Seong-Gook | 6-4,6-1 |
| ITF - M15 Antalya | 2021/03/28 06:30 | Dabryian, Artsiom v Oh, Seong-Gook | 1-6,3-6 |
| Nonthaburi, Singles M-ITF-THA-01A | 2020/02/02 04:15 | Oh, Seong-Gook v Broville, Maxence | 6-7,1-6 |
| Nonthaburi, Singles M-ITF-THA-01A | 2020/01/27 06:50 | Oh, Seong-Gook v Nam Hoang Ly | 2-6,6-7 |
| Nonthaburi, Singles M-ITF-THA-01A | 2020/01/26 11:00 | Oh, Seong-Gook v Noikor, Noppadol | 6-0,6-3 |
| ITF M15 St Petersburg | 2021/04/15 09:00 | Daniil Glinka v Marat Sharipov | 2-6,3-6 |
| ITF M15 St Petersburg | 2021/04/14 13:10 | Satral, Jan v Daniil Glinka | 4-6,2-6 |
| ITF M15 St Petersburg | 2021/04/12 08:30 | Daniil Glinka v Alexander Zgirovsky | 7-6,7-6 |
| ITF M15 St Petersburg Qual | 2021/04/11 11:00 | Daniil Glinka v Stepin, Alexander | 6-4,6-3 |
| ITF M15 St Petersburg | 2021/04/08 09:00 | Daniil Glinka v Satral, Jan | 4-6,3-6 |
| ITF M15 St Petersburg | 2021/04/06 14:25 | Daniil Glinka v Daniil Golubev | 6-0,6-0 |
| ITF M15 St Petersburg | 2021/04/05 11:00 | Daniil Glinka v Yannik Steinegger | 6-2,6-2 |
| ITF M15 St Petersburg | 2021/04/04 10:05 | Daniil Glinka v Stepan Pecak | 7-5,6-1 |