| ITF Japan F6 Qual | 2017/05/27 01:00 | Watanuki, Keisuke v Han, Sung Min | 6-4,6-0 |
| ITF Japan F5 | 2017/04/02 01:00 | Sasai, Masaki v Watanuki, Keisuke | 6-2,6-4 |
| ITF Japan F5 | 2017/04/01 02:00 | Yasugami, Takashi v Watanuki, Keisuke | 4-6,6-2,5-7 |
| ITF Japan F4 | 2017/03/28 01:00 | 코바야시, 마사야 v Watanuki, Keisuke | 6-3,6-2 |
| ITF Japan F4 | 2017/03/27 01:00 | 타시로, 유가 v Watanuki, Keisuke | 2-6,6-7 |
| ITF Japan F4 | 2017/03/25 03:00 | Chang, Yu v Watanuki, Keisuke | 7-6,3-6,4-6 |
| ITF Japan F2 | 2017/03/14 04:20 | 타카하시, 유스케 v Watanuki, Keisuke | 6-2,6-2 |
| ITF Japan F2 | 2017/03/13 01:00 | Wachiramanowong, Kittiphong v Watanuki, Keisuke | 4-6,6-7 |
| ITF Japan F5 | 2017/04/01 01:00 | Sakai, Yuto v 니시와키, 카즈키 | 2-6,6-7 |
| ITF Japan F3 | 2017/03/18 06:00 | Vinsant, Shane v Sakai, Yuto | 6-3,6-2 |
| ITF Japan F3 | 2017/03/18 00:30 | Shirafuji, Naru v Sakai, Yuto | 3-6,4-6 |
| ITF Japan F1 | 2017/03/05 01:00 | 코바야시, 마사야 v Sakai, Yuto | 7-6,7-5 |
| ITF Japan F1 | 2017/03/04 03:30 | Sakai, Yuto v Nakamura, Yuki | 7-6,7-5 |
| ITF Indonesia F3 | 2017/02/22 06:50 | Matsuzaki, Yutaro v Sakai, Yuto | 6-4,6-4 |
| ITF Indonesia F3 Qual | 2017/02/20 02:30 | 로, 치엔순 v Sakai, Yuto | 1-6,6-1,6-7 |
| ITF Indonesia F3 Qual | 2017/02/19 06:30 | Sakai, Yuto v Foo, Sherwin | 6-4,6-1 |