Round: 44 Ground: Clay
| ITF Japan F4 | 2016/03/27 01:00 | Yosuke Watanuki v Onishi, Ken | 6-2,7-6 |
| ITF Japan F3 | 2016/03/23 01:00 | Kibi, Yuya v Onishi, Ken | 7-6,6-1 |
| ITF Japan F3 | 2016/03/22 03:10 | Onishi, Ken v Watanuki, Keisuke | 2-6,6-2,7-5 |
| ITF Japan F2 | 2016/03/12 02:00 | Tung-Lin Wu v Onishi, Ken | 6-2,6-2 |
| ITF Kuwait F3 | 2015/11/26 08:00 | Onishi, Ken v Evgeny Karlovskiy | 3-6,2-6 |
| ITF Kuwait F3 | 2015/11/25 12:30 | Onishi, Ken v Ghareeb, Ali | 6-3,6-2 |
| ITF Kuwait F3 | 2015/11/23 10:15 | Martos Gornes, Sergio v Onishi, Ken | 4-6,1-6 |
| ITF Kuwait F2 | 2015/11/18 09:00 | Onishi, Ken v Monteban, Paul | 6-7,6-7 |