Round: 25 Ground: Hardcourt outdoor
| ITF Japan F3 | 2018/03/19 03:15 | Shinji Hazawa v Niki, Takuto | 7-5,6-3 |
| ITF Japan F2 | 2018/03/13 02:00 | Kaito Uesugi v Niki, Takuto | 6-0,6-3 |
| ITF Japan F1 | 2018/03/10 02:00 | Nguyen, Daniel v Niki, Takuto | 6-3,6-4 |
| ITF Japan F1 | 2018/03/09 02:00 | Niki, Takuto v Moritani, Soichiro | 6-1,6-4 |
| ITF Japan F1 | 2018/03/08 03:10 | Niki, Takuto v Kibi, Yuya | 6-3,7-5 |
| ITF Japan F1 | 2018/03/07 04:45 | Niki, Takuto v Maesaki, Naoya | 6-2,6-7,6-2 |
| Yokohama, Japan, Qualifying | 2018/02/25 02:35 | Yunseong Chung v Niki, Takuto | 6-7,6-3,6-3 |
| Yokohama, Japan, Qualifying | 2018/02/24 07:05 | Niki, Takuto v Balaji, N. Sriram | 3-6,7-6,7-5 |
| ITF Japan F3 | 2018/03/19 06:00 | Hong, Seong Chan v Naoki Tajima | 6-1,4-6,6-4 |
| ITF Japan F5 | 2017/04/04 02:30 | Naoki Tajima v Toshihide Matsui | 6-1,4-6,3-6 |
| ITF Japan F5 | 2017/04/02 01:00 | Oku, Hiromasa v Naoki Tajima | 1-6,0-6 |
| ITF Japan F5 | 2017/04/01 02:00 | Yuichiro Inui v Naoki Tajima | 4-6,0-6 |
| ITF Japan F4 | 2017/03/29 05:40 | Naoki Tajima v Yusuke Takahashi | 6-3,1-6,4-6 |
| Challenger Kyoto Qual | 2017/02/18 04:20 | Evgeny Karlovskiy v Naoki Tajima | 6-3,6-1 |
| ITF Japan F1 | 2016/03/05 03:00 | Tung-Lin Wu v Naoki Tajima | 6-4,5-7,6-4 |