Stadium: Center Court Round: 45
| Jinan, China | 2018/08/06 02:00 | Wang, Tak Khunn v Issei Okamura | 6-1,6-2 |
| Jinan, China | 2018/08/05 02:00 | Lo, Chien Hsun v Issei Okamura | 6-7,1-6 |
| Challenger Chengdu Qual | 2018/07/28 03:35 | Issei Okamura v Blake Ellis | 6-4,1-6,5-7 |
| ITF Chinese Taipei F2 | 2018/07/26 02:00 | Issei Okamura v Chun Hsin Tseng | 3-6,4-6 |
| ITF Chinese Taipei F2 | 2018/07/24 02:00 | Issei Okamura v Lin, Liang Yu Richard | 6-2,6-2 |
| ITF Chinese Taipei F1 | 2018/07/19 04:05 | Yu Hsiou Hsu v Issei Okamura | 7-6,7-5 |
| ITF Chinese Taipei F1 | 2018/07/18 03:50 | Issei Okamura v Vilardo, Francesco | 7-5,6-4 |
| ITF Hong Kong F2 | 2018/07/05 02:00 | Issei Okamura v Shintaro Imai | 2-6,1-6 |
| ITF Korea F1 | 2018/06/06 01:00 | Na, Jung-Woong v Ji Hoon Son | 6-4,6-7,6-4 |
| Challenger - Busan | 2018/05/15 05:50 | Max Purcell v Na, Jung-Woong | 6-4,6-1 |
| Challenger Gimcheon Qual | 2018/05/05 05:20 | Grills, Jacob v Na, Jung-Woong | 5-7,6-4,6-3 |
| Challenger Seoul Qual | 2018/04/29 02:00 | Na, Jung-Woong v Makoto Ochi | 2-6,4-6 |
| Challenger Seoul Qual | 2018/04/28 03:05 | Na, Jung-Woong v Lee, Tae-Woo | 6-1,6-3 |
| ITF Turkey F5 | 2018/02/08 07:30 | Na, Jung-Woong v Nino Serdarusic | 1-6,2-6 |
| ITF Turkey F5 | 2018/02/06 07:30 | Codescu, Razvan Marius v Na, Jung-Woong | 3-6,0-6 |
| ITF Turkey F5 | 2018/02/05 07:30 | Na, Jung-Woong v Luka Miklavcic | 6-4,6-0 |