Stadium: Court 1 Round: 25 Ground: Hardcourt outdoor
| Challenger Kobe | 2018/11/10 06:00 | Xin Gao v Kazuki Nishiwaki | 6-4,6-4 |
| Challenger Nanchang | 2019/04/22 04:35 | Ben Patael v Xin Gao | 6-1,6-4 |
| Challenger Anning | 2019/04/15 10:10 | Xin Gao v Matteo Viola | 3-6,1-6 |
| Challenger Zhangjiagang | 2019/03/18 05:40 | Xin Gao v Di Wu | 5-7,4-6 |
| Challenger Zhuhai | 2019/03/04 07:05 | Xin Gao v Alex Molcan | 5-7,4-6 |
| ITF M25 Glasgow | 2019/02/18 18:05 | Xin Gao v Alexander Ritschard | 4-6,2-6 |
| ITF M25 Glasgow | 2019/02/18 11:40 | Xin Gao v Joshua Paris | 7-6,3-6,10-8 |
| ITF M25 Barnstaple | 2019/02/11 10:00 | Xin Gao v Julian Cash | 5-7,1-6 |
| Challenger Canberra | 2019/01/07 06:50 | Sem Verbeek v Xin Gao | 1-6,7-6,6-3 |
| ITF M25 Matsuyama | 2019/04/10 07:40 | Rinky Hijikata v Kazuki Nishiwaki | 6-3,6-4 |
| ITF M15 Kashiwa | 2019/04/01 06:00 | Kuan-Yi Lee v Kazuki Nishiwaki | 6-4,6-4 |
| ITF M15 Kashiwa | 2019/04/01 00:00 | Daisuke Sumizawa v Kazuki Nishiwaki | 6-2,2-6,8-10 |
| ITF M15 Tsukuba | 2019/03/27 01:00 | Makoto Ochi v Kazuki Nishiwaki | 6-3,6-1 |
| ITF M15 Kofu | 2019/03/20 05:10 | Mick Veldheer v Kazuki Nishiwaki | 4-6,6-1,6-4 |
| ITF M15 Sharm El Sheikh | 2019/02/18 12:15 | Kazuki Nishiwaki v Giorgio Ricca | 7-5,6-7,6-10 |
| ITF M15 Sharm El Sheikh | 2019/02/18 07:30 | Kazuki Nishiwaki v Mathys Erhard | 6-0,6-1 |
| ITF M15 Anning | 2019/01/12 05:05 | Kazuki Nishiwaki v Agustin Velotti | 6-7,2-6 |