Ground: Hardcourt outdoor
| ITF Thailand F9 | 2015/04/18 04:00 | Nagao, Katsuki v Nalamphun, Jatuporn | 6-0,6-2 |
| ITF Japan F3 | 2015/03/22 01:00 | Nakamura, Yuki v Nagao, Katsuki | 7-6,6-0 |
| ITF Japan F2 | 2015/03/18 02:55 | Duckhee Lee v Nagao, Katsuki | 6-3,7-5 |
| ITF Japan F2 | 2015/03/16 01:00 | Ho, Chih-Jen v Nagao, Katsuki | 4-6,4-6 |
| ITF Japan F1 | 2015/03/10 03:50 | Nagao, Katsuki v Duckhee Lee | 2-6,3-6 |
| ITF Turkey F34 | 2014/10/01 08:35 | Marshall Tutu v Nagao, Katsuki | 6-3,6-1 |
| ITF Turkey F34 | 2014/09/29 07:00 | Nagao, Katsuki v Yvo Panak | 6-3,6-0 |
| ITF Turkey F34 | 2014/09/28 07:00 | Nagao, Katsuki v Watanuki, Keisuke | 6-3,5-7,7-6 |
| ITF Thailand F9 | 2015/04/18 04:00 | Ratiwatana, Sonchat v Syed Naguib, Syed Mohd Agil | 6-3,6-1 |
| ITF Japan F4 | 2015/03/29 00:00 | Chaplin, Jarryd v Ratiwatana, Sonchat | 5-7,6-3,6-2 |