Stadium: Court 1 Round: 44 Ground: Hardcourt outdoor
| ITF - M15 Sharm-el-Sheikh | 2020/02/12 08:00 | Pablo Vivero Gonzalez v Piotr Grynkowski | 6-3,6-3 |
| ITF - M15 Sharm-el-Sheikh | 2020/02/11 08:00 | Volodymyr Uzhylovskyi v Piotr Grynkowski | 6-4,6-4 |
| ITF - M15 Sharm-el-Sheikh | 2020/02/10 09:00 | Victor Ernaelsteen v Piotr Grynkowski | 2-6,2-6 |
| ITF - M15 Sharm-el-Sheikh | 2020/02/09 10:00 | Shinnosuke Hiramatsu v Piotr Grynkowski | 3-6,0-6 |
| ITF M15 Milovice | 2019/11/14 13:45 | Piotr Grynkowski v Vadym Ursu | 2-6,1-6 |
| ITF M15 Milovice | 2019/11/13 09:00 | Piotr Grynkowski v Samuel Puskar | 6-3,6-0 |
| ITF M15 Milovice | 2019/11/12 10:30 | Piotr Grynkowski v Jiri Barnat | 6-4,6-4 |
| ITF M15 Milovice | 2019/11/11 09:00 | Piotr Grynkowski v Christopher Patzanovsky | 6-1,2-6,10-5 |
| ITF M15 - Hongkong | 2020/01/08 09:30 | Makoto Ochi v Ken Onishi | 7-6,6-2 |
| ITF M15 - Hongkong | 2020/01/07 04:45 | Kousuke Ogura v Ken Onishi | 5-7,4-6 |
| ITF M15 - Hongkong | 2020/01/06 02:00 | Shohei Chikami v Ken Onishi | 4-6,1-6 |
| ITF M15 - Te Anau | 2019/12/30 23:00 | Elliot Benchetrit v Ken Onishi | 7-5,6-1 |
| Challenger - Kobe | 2019/11/06 01:30 | Luke Saville v Ken Onishi | 6-2,6-2 |
| ITF M25 Taipei | 2019/07/22 04:00 | Han-Chih Lin v Ken Onishi | 6-7,6-3,10-6 |
| ITF M25 Taipei | 2019/07/15 02:00 | Hao-Hsiang Liao v Ken Onishi | 7-6,7-6 |
| ITF M15 Gimcheon | 2019/06/17 05:20 | Ju-Hae Moon v Ken Onishi | 2-6,6-3,10-6 |