Stadium: Court 5 Round: 25 Ground: Clay
| ITF Japan F6 Qual | 2018/04/08 01:00 | Issei Okamura v Hikaru Shiraishi | 6-4,6-3 |
| ITF Japan F7 | 2016/06/07 05:10 | Ito, Yuichi v Hikaru Shiraishi | 6-1,6-0 |
| ITF Japan F8 | 2018/06/11 00:30 | Sakai, Yuto v Tashiro, Yuga | 7-5,7-6 |
| ITF Japan F8 | 2018/06/09 01:00 | Sakai, Yuto v Mariyappa, Arjun | 6-0,6-0 |
| ITF Japan F6 Qual | 2018/04/09 01:00 | Issei Okamura v Sakai, Yuto | 6-2,6-3 |
| ITF Japan F6 Qual | 2018/04/08 01:00 | Azuma, Ryuhei v Sakai, Yuto | 2-6,2-6 |
| ITF Japan F3 | 2018/03/17 02:30 | Kousuke Ogura v Sakai, Yuto | 6-4,6-3 |
| ITF Japan F2 | 2018/03/13 04:00 | Tanaka, Yunosuke v Sakai, Yuto | 6-4,4-6,7-6 |
| ITF Japan F2 | 2018/03/12 00:30 | Sakai, Yuto v Takeshima, Shunrou | 6-4,6-2 |
| ITF Japan F2 | 2018/03/11 04:00 | Kikuchi, Gengo v Sakai, Yuto | 2-6,2-6 |