Round: 25 Ground: Hardcourt outdoor
| ITF Japan F8 | 2016/06/15 06:25 | Issei Okamura v Yusuke Takahashi | 3-6,0-6 |
| Challenger Anning Qual | 2017/04/22 03:35 | Issei Okamura v Denys Molchanov | 6-4,3-6,4-6 |
| Challenger Taipei Qual | 2017/04/17 04:35 | Ruan Roelofse v Issei Okamura | 6-4,6-2 |
| Challenger Taipei Qual | 2017/04/16 05:55 | Shao-Fan Liu v Issei Okamura | 6-7,6-4,3-6 |
| ITF Japan F5 | 2017/04/04 00:30 | Issei Okamura v Takao Suzuki | 6-7,3-6 |
| ITF Japan F4 | 2017/03/28 03:00 | Kaito Uesugi v Issei Okamura | 6-3,6-3 |
| ITF Japan F3 | 2017/03/22 06:00 | Shane Vinsant v Issei Okamura | 6-2,6-3 |
| ITF Japan F3 | 2017/03/20 02:35 | Daisuke Sumizawa v Issei Okamura | 2-6,2-6 |
| ITF Japan F2 | 2017/03/13 04:00 | Issei Okamura v Nam Hoang Ly | 2-6,2-6 |
| ITF Japan F5 | 2017/04/09 03:30 | Tatsuma Ito v Yusuke Takahashi | 6-4,6-2 |
| ITF Japan F5 | 2017/04/07 07:10 | Yusuke Takahashi v Sho Katayama | 6-1,7-5 |
| ITF Japan F5 | 2017/04/06 02:50 | Yusuke Takahashi v Yuki Matsuo | 6-2,6-3 |
| ITF Japan F5 | 2017/04/04 02:50 | Yusuke Takahashi v Collin Johns | 6-3,6-1 |
| ITF Japan F4 | 2017/04/02 02:00 | Takuto Niki v Yusuke Takahashi | 2-6,2-6 |
| ITF Japan F4 | 2017/04/01 01:00 | Seong Chan Hong v Yusuke Takahashi | 4-6,5-7 |
| ITF Japan F4 | 2017/03/31 01:00 | Ryota Tanuma v Yusuke Takahashi | 3-6,2-6 |
| ITF Japan F4 | 2017/03/30 03:00 | Yuichi Ito v Yusuke Takahashi | 3-6,3-6 |