Stadium: Court 7 Round: 26
| ITF Malaysia F2 | 2018/07/10 03:50 | Rhett Purcell v Seong-Gook Oh | 7-6,7-5 |
| ITF Malaysia F1 | 2018/07/04 03:30 | Soichiro Moritani v Seong-Gook Oh | 6-4,6-0 |
| ITF Malaysia F1 | 2018/07/03 10:05 | Seong-Gook Oh v Sang-Woo Noh | 7-6,6-2 |
| ITF Korea F3 | 2018/06/18 03:30 | Seong-Gook Oh v Seong Chan Hong | 6-7,0-6 |
| ITF Korea F2 | 2018/06/13 03:05 | Seong-Gook Oh v Chukang Wang | 6-1,5-7,7-5 |
| ITF Korea F1 | 2018/06/05 01:00 | Seong-Gook Oh v Jae-Won Choi | 1-6,5-7 |
| Challenger Busan Qual | 2018/05/12 02:15 | Jeamoon Lee v Seong-Gook Oh | 7-6,6-3 |
| Challenger Seoul Qual | 2018/04/28 02:50 | Ji Hoon Son v Seong-Gook Oh | 6-3,6-3 |
| ITF Korea F4 | 2018/08/14 02:30 | Oh-Hee Kwon v Seong Taek Im | 6-3,6-4 |
| ITF Korea F3 | 2018/06/22 03:00 | Yunseong Chung v Oh-Hee Kwon | 6-4,6-1 |
| ITF Korea F3 | 2018/06/20 02:30 | Oh-Hee Kwon v Seong Chan Hong | 7-5,6-4 |
| ITF Korea F3 | 2018/06/19 06:35 | Cing-Yang Meng v Oh-Hee Kwon | 1-6,2-6 |
| ITF Korea F3 Qual | 2018/06/18 06:30 | Hyeong Don Kim v Oh-Hee Kwon | 2-6,2-6 |
| ITF Korea F3 Qual | 2018/06/17 04:30 | Seong Jae Han v Oh-Hee Kwon | 4-6,1-6 |
| ITF Korea F3 Qual | 2018/06/16 03:30 | Ki Su Jung v Oh-Hee Kwon | 0-6,1-6 |
| ITF Korea F1 | 2018/06/04 02:20 | Oh-Hee Kwon v Alec Adamson | 5-7,4-6 |