Stadion: Court 2 Round: 54 Ground: Hardcourt outdoor
| ITF - M15 - Daegu | 2019/06/03 02:40 | Ken Onishi v Sin Woo Lee | 6-1,6-7,10-1 |
| ITF - M15 - Tabarka | 2019/05/15 12:40 | Ken Onishi v Nicolas Bianchi | 6-4,1-6,4-6 |
| ITF - M15 - Tabarka | 2019/05/09 08:30 | Ken Onishi v Mathieu Perchicot | 0-6,0-6 |
| ITF - M15 - Tabarka | 2019/05/08 09:40 | Kazuma Kawachi v Ken Onishi | 7-6,5-7,0-6 |
| ITF - M15 - Tabarka | 2019/05/01 11:10 | Florian Lakat v Ken Onishi | 6-3,4-6,6-0 |
| ITF - M15 - Tabarka | 2019/04/29 08:00 | Mason Recci v Ken Onishi | 4-6,1-6 |
| ITF M25 Matsuyama | 2019/04/09 02:50 | Gage Brymer v Ken Onishi | 7-6,6-2 |
| ITF - M15 - Tsukuba | 2019/03/25 01:00 | Ryuki Matsuda v Ken Onishi | 6-2,6-3 |
| ITF - M15 - Daegu | 2019/06/03 02:40 | Jung Ho Shin v Young Seok Lee | 4-6,3-6 |
| Challenger - Busan | 2019/05/06 02:00 | Makoto Ochi v Young Seok Lee | 6-3,6-4 |
| ITF - M15 - Anning | 2019/01/14 05:30 | Grigoriy Lomakin v Young Seok Lee | 6-1,4-6,13-11 |
| ITF - M15 - Anning | 2019/01/14 01:30 | Young Seok Lee v Ruikai Ruikai Wang | 6-3,5-7,10-3 |
| ITF - M15 - Anning | 2018/12/31 01:30 | Young Seok Lee v Ye Cong Mo | 2-6,6-1,3-10 |
| ITF - Korea F5 | 2018/08/18 01:00 | Young Seok Lee v Seoung Hun Lee | 3-6,2-6 |
| ITF - Korea F4 | 2018/08/16 03:05 | Young Seok Lee v Uisung Park | 2-6,0-6 |
| ITF - Korea F4 | 2018/08/14 01:00 | Aaron Addison v Young Seok Lee | 6-0,3-6,2-6 |