Round: 25 Ground: Clay
| 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 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 Singapore F1 Qual | 2017/05/21 04:00 | Onozawa, Arata v Look, Michael | 4-6,7-6,4-6 |
| ITF Japan F3 | 2017/03/19 01:00 | Onozawa, Arata v 카와카미, 림페이 | 3-6,6-2,2-6 |
| ITF Japan F3 | 2017/03/18 06:00 | Onozawa, Arata v 푸지이, 소타 | 6-4,6-3 |
| Challenger Kyoto Qual | 2017/02/19 05:25 | Wang, Jimmy v Onozawa, Arata | 6-3,6-4 |
| Challenger Kyoto Qual | 2017/02/18 07:35 | Onozawa, Arata v 타카하시, 유스케 | 6-3,6-7,6-3 |
| Others | 2016/11/12 07:35 | Takeuchi, Kento (1987) v Onozawa, Arata | 7-6,6-2 |
| Others | 2016/11/12 02:10 | 오니시, 켄 v Onozawa, Arata | 3-6,4-6 |
| ITF Vietnam F4 | 2016/09/15 03:00 | Onozawa, Arata v 콩카르, 콩섭 | 5-7,4-6 |