Round: 25 Ground: Hardcourt outdoor
| ITF Japan F6 | 2015/06/10 03:10 | Sasai, Masaki v Sekiguchi, Shuichi | 7-6,7-5 |
| Challenger Launceston | 2016/02/02 04:20 | Alex Bolt v Sekiguchi, Shuichi | 6-3,6-4 |
| Challenger Shanghai | 2015/10/10 05:40 | Nikoloz Basilashvili v Sekiguchi, Shuichi | 6-4,6-2 |
| WTA Kuala Lumpur Qual | 2015/09/26 02:00 | Begemann, Andre v Sekiguchi, Shuichi | 2-6,6-2,6-3 |
| Challenger Kaohsiung Qual | 2015/09/20 06:50 | Sekiguchi, Shuichi v Yi, Chu-Huan | 4-6,4-6 |
| Challenger Granby | 2015/07/23 15:00 | Sekiguchi, Shuichi v Donati, Matteo | 4-6,1-6 |
| ITF Thailand F9 | 2015/06/27 03:00 | Rungkat, Christopher v Sekiguchi, Shuichi | 6-4,6-3 |
| ITF Thailand F9 | 2015/06/26 03:00 | Sekiguchi, Shuichi v Na, Jung-Woong | 6-4,6-3 |
| ITF Thailand F9 | 2015/06/25 03:00 | Sekiguchi, Shuichi v Singh, Karunuday | 6-0,6-2 |
| ITF Japan F1 | 2016/03/06 01:00 | Yuki Mochizuki v Sasai, Masaki | 6-7,4-6 |
| ITF Japan F1 | 2016/03/05 01:00 | Chiu, Yu Hsiang v Sasai, Masaki | 7-5,3-6,4-6 |
| ITF Japan F8 | 2015/06/25 01:00 | Katayama, Sho v Sasai, Masaki | 6-3,6-1 |
| ITF Japan F7 | 2015/06/17 01:00 | Sasai, Masaki v Ryota Tanuma | 1-6,3-6 |
| ITF Japan F6 | 2015/06/12 05:30 | Niki, Takuto v Sasai, Masaki | 6-2,6-1 |
| ITF Japan F6 | 2015/06/11 01:00 | Yosuke Watanuki v Sasai, Masaki | 3-6,2-6 |
| ITF Japan F6 | 2015/06/10 03:10 | Sasai, Masaki v Sekiguchi, Shuichi | 7-6,7-5 |
| ITF Japan F5 | 2015/06/03 06:30 | Saito, Takashi v Sasai, Masaki | 6-0,6-2 |