Round: 25 Ground: Hardcourt outdoor
| ITF Japan F1 | 2016/03/07 01:00 | Nagao, Katsuki v Moritani, Soichiro | 6-4,7-6 |
| ITF Japan F1 | 2016/03/05 01:00 | Nagao, Katsuki v Masaya Kobayashi | 6-2,2-6,6-3 |
| ITF Japan F8 | 2015/06/27 01:00 | Yasutaka Uchiyama v Nagao, Katsuki | 7-6,6-3 |
| ITF Japan F8 | 2015/06/25 04:25 | Ehara, Hiroyasu v Nagao, Katsuki | 4-6,3-6 |
| ITF Japan F8 | 2015/06/24 01:10 | Nagao, Katsuki v Osafune, Masaki | 6-3,6-0 |
| ITF Japan F7 | 2015/06/18 02:00 | Tanuma, Ryota v Nagao, Katsuki | 6-3,6-1 |
| ITF Japan F7 | 2015/06/17 01:00 | Takeshima, Shunrou v Nagao, Katsuki | 6-7,3-6 |
| ITF Japan F6 | 2015/06/10 01:30 | Yosuke Watanuki v Nagao, Katsuki | 7-6,6-7,6-4 |
| ITF Turkey F5 | 2016/02/03 08:00 | Gigounon, Germain v Watanuki, Yusuke | 6-1,4-6,6-4 |
| ITF Turkey F4 | 2016/01/26 11:05 | Watanuki, Yusuke v Tallon Griekspoor | 3-6,1-6 |
| ITF Turkey F3 | 2016/01/22 13:40 | Joris De Loore v Watanuki, Yusuke | 6-3,6-0 |
| ITF Turkey F3 | 2016/01/22 09:00 | Altug Celikbilek v Watanuki, Yusuke | 3-6,6-7 |
| ITF Turkey F3 | 2016/01/19 08:00 | Wagner, Hannes v Watanuki, Yusuke | 5-7,1-6 |
| ITF Australia F7 | 2015/10/08 03:00 | Watanuki, Yusuke v Tearney, Finn | 6-1,1-6,3-6 |
| ITF Australia F7 | 2015/10/07 01:15 | Watanuki, Yusuke v Nolan, Daniel | 6-1,6-3 |
| ITF Australia F6 | 2015/10/01 03:10 | Stanek, Robin v Watanuki, Yusuke | 6-3,7-6 |