Round: 26 Ground: Clay
| ITF Japan F8 | 2017/06/14 01:00 | Sakai, Yuto v Ono, Yohei | 7-5,6-0 |
| ITF Japan F8 | 2017/06/12 00:00 | Luca Castelnuovo v Sakai, Yuto | 7-6,4-6,6-7 |
| ITF Japan F8 | 2017/06/11 03:00 | Sakai, Yuto v Shinji Hazawa | 6-1,6-4 |
| ITF Japan F6 | 2017/06/01 04:10 | Sakai, Yuto v Sora Fukuda | 6-7,3-6 |
| ITF Japan F6 | 2017/05/31 01:00 | Sakai, Yuto v Sora Fukuda | 6-7,3-6 |
| ITF Japan F6 | 2017/05/30 03:30 | Sakai, Yuto v Onozawa, Arata | 7-6,7-5 |
| ITF Japan F6 Qual | 2017/05/29 01:00 | Watanuki, Keisuke v Sakai, Yuto | 6-7,6-7 |
| ITF Japan F6 Qual | 2017/05/28 07:00 | Watanuki, Keisuke v Sakai, Yuto | 6-7,6-7 |
| ITF Japan F8 | 2017/06/14 01:00 | Habusawa, Tetsuro v Watanuki, Yusuke | 3-6,3-6 |
| ITF Japan F7 | 2017/06/06 01:00 | Niki, Takuto v Watanuki, Yusuke | 5-7,7-5,6-4 |
| ITF Japan F6 | 2017/05/29 05:50 | Watanuki, Yusuke v Shintaro Imai | 0-6,5-7 |
| ITF Japan F5 | 2017/04/09 03:30 | Watanuki, Yusuke v Shiga, Masato | 6-7,5-7 |
| ITF Japan F5 | 2017/04/09 03:00 | Watanuki, Yusuke v Shiga, Masato | 6-7,5-7 |
| ITF Japan F5 | 2017/04/07 04:30 | Watanuki, Yusuke v Shintaro Imai | 6-1,6-3 |
| ITF Japan F5 | 2017/04/05 00:30 | Suzuki, Takao v Watanuki, Yusuke | 2-6,1-6 |
| ITF Japan F5 | 2017/04/04 04:30 | Watanuki, Yusuke v Sasai, Masaki | 6-2,6-2 |