Stadium: Court C Round: 62 Ground: Hardcourt outdoor
| ITF Japan F1 | 2018/03/03 01:00 | Okagaki, Kosuke v Kai, Naoto | 6-4,0-6,2-6 |
| Yokohama, Japan, Qualifying | 2018/02/24 03:55 | Garanganga, Takanyi v Kai, Naoto | 6-3,4-6,7-6 |
| ITF Japan F8 | 2017/06/10 05:00 | Goh, Steven v Kai, Naoto | 6-3,6-2 |
| ITF Japan F7 | 2017/06/06 01:00 | Shintaro Imai v Kai, Naoto | 6-1,6-2 |
| ITF Japan F6 Qual | 2017/05/27 01:00 | Furuta, Ibuki v Kai, Naoto | 6-2,6-0 |
| ITF Japan F4 | 2017/03/25 00:00 | Nakamura, Yuki v Kai, Naoto | 6-4,4-6,6-1 |
| ITF Japan F1 | 2017/03/04 03:30 | Furuta, Ibuki v Kai, Naoto | 6-2,6-0 |
| ITF Japan F7 | 2016/06/06 01:00 | Tanuma, Ryota v Kai, Naoto | 6-4,6-3 |
| ITF Japan F1 | 2018/03/03 01:00 | Uesugi, Teppei v Itsusaki, Kaito | 7-6,0-6,2-6 |
| Challenger Yokohama | 2018/02/27 01:00 | Soeda, Go v Itsusaki, Kaito | 6-0,6-2 |
| Challenger Kyoto Qual | 2018/02/17 07:50 | Itsusaki, Kaito v Niki, Takuto | 4-6,0-6 |
| ITF Japan F7 | 2017/06/03 01:00 | Itsusaki, Kaito v Uesugi, Teppei | 6-7,6-1,3-6 |
| ITF Japan F6 | 2017/05/31 01:00 | Itsusaki, Kaito v Shintaro Imai | 6-3,1-6,3-6 |
| ITF Japan F6 | 2017/05/29 04:00 | Yosuke Watanuki v Itsusaki, Kaito | 1-6,7-6,1-6 |
| ITF Japan F5 | 2017/04/01 01:00 | Itsusaki, Kaito v Masamichi Imamura | 3-6,4-6 |
| ITF Japan F4 | 2017/03/29 01:00 | Kikuchi, Gengo v Itsusaki, Kaito | 6-4,6-3 |