Round: 25 Ground: Hardcourt outdoor
| ITF Japan F6 | 2015/06/11 02:55 | Takuto Niki v Keisuke Watanuki | 6-7,7-6,6-4 |
| ITF Japan F3 | 2014/03/26 02:50 | Takuto Niki v Keisuke Watanuki | 6-3,6-1 |
| Challenger Kaohsiung | 2015/09/23 08:05 | Takuto Niki v Hyeon Chung | 2-6,4-6 |
| Challenger Kaohsiung | 2015/09/22 08:10 | Jui-Chen Hung v Takuto Niki | 2-6,2-6 |
| Challenger Aptos | 2015/08/11 17:00 | Kyle Edmund v Takuto Niki | 6-1,6-2 |
| Challenger Aptos Qual | 2015/08/10 19:40 | Tennys Sandgren v Takuto Niki | 6-3,7-5 |
| ATP Washington Qual | 2015/08/01 15:50 | Sekou Bangoura v Takuto Niki | 3-6,7-6,6-7 |
| ITF Japan F8 | 2015/06/25 01:00 | Renta Tokuda v Takuto Niki | 2-6,7-6,6-3 |
| ITF Japan F8 | 2015/06/24 03:45 | Woong-Sun Jun v Takuto Niki | 2-6,6-2,4-6 |
| ITF Japan F6 | 2015/06/13 01:30 | Takuto Niki v Toshihide Matsui | 3-6,2-6 |
| ITF Japan F8 | 2015/06/25 01:00 | Keisuke Numajiri v Keisuke Watanuki | 3-6,3-6 |
| ITF Japan F8 | 2015/06/24 02:45 | Keisuke Watanuki v Yuichi Ito | 6-1,7-5 |
| ITF Japan F7 | 2015/06/16 02:15 | Arata Onozawa v Keisuke Watanuki | 7-6,0-6,6-3 |
| ITF Japan F6 | 2015/06/11 02:55 | Takuto Niki v Keisuke Watanuki | 6-7,7-6,6-4 |
| ITF Japan F6 | 2015/06/10 01:30 | Keisuke Watanuki v Hiromasa Oku | 6-2,6-3 |
| ITF Japan F5 | 2015/06/04 02:00 | Thomas Fancutt v Keisuke Watanuki | 7-5,7-6 |
| ITF Japan F5 | 2015/06/03 06:30 | Ryotaro Matsumura v Keisuke Watanuki | 6-2,4-6,0-6 |
| ITF Greece F9 | 2015/04/29 10:05 | David Simunek v Keisuke Watanuki | 6-4,6-2 |