Round: 25 Ground: Hardcourt outdoor
| ITF Japan F3 | 2018/03/19 03:15 | Shinji Hazawa v Takuto Niki | 7-5,6-3 |
| ITF Japan F2 | 2018/03/13 02:00 | Kaito Uesugi v Takuto Niki | 6-0,6-3 |
| ITF Japan F1 | 2018/03/10 02:00 | Daniel Nguyen v Takuto Niki | 6-3,6-4 |
| ITF Japan F1 | 2018/03/09 02:00 | Takuto Niki v Soichiro Moritani | 6-1,6-4 |
| ITF Japan F1 | 2018/03/08 03:10 | Takuto Niki v Yuya Kibi | 6-3,7-5 |
| ITF Japan F1 | 2018/03/07 04:45 | Takuto Niki v Naoya Maesaki | 6-2,6-7,6-2 |
| Challenger Yokohama Qual | 2018/02/25 02:35 | Yunseong Chung v Takuto Niki | 6-7,6-3,6-3 |
| Challenger Yokohama Qual | 2018/02/24 07:05 | Takuto Niki v N.Sriram Balaji | 3-6,7-6,7-5 |
| ITF Japan F3 | 2018/03/19 06:00 | Seong Chan Hong 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 | Hiromasa Oku 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 |