Stadium: Court 7 Round: 44
| ITF Women Gyeongsan Qual | 2018/06/11 03:30 | Li, Jiakang v Yoon, Sujin | 3-6,0-6 |
| ITF Women Gyeongsan Qual | 2018/06/10 03:30 | Jeong, Jooyeon v Yoon, Sujin | 0-6,1-6 |
| ITF Women Sangju Qual | 2018/06/05 01:00 | Ho Ching Wu v Yoon, Sujin | 6-1,6-0 |
| ITF Women Sangju Qual | 2018/06/03 01:00 | Yoon, Sujin v Yoon, So-Hee | 2-6,6-3,6-2 |
| ITF Women Incheon Qual | 2018/05/13 02:00 | Yoon, Sujin v Dabin Kim | 3-6,6-0,4-6 |
| ITF Women Goyang Qual | 2018/05/06 05:15 | Yoon, Sujin v Lee, Hye-Jin | 2-6,6-3,5-7 |
| ITF Women Yeongwol | 2017/09/03 03:00 | Yoon, Sujin v Kamiyoshihara, Ai | 5-7,2-6 |
| ITF Women Yeongwol | 2017/08/28 01:00 | Yoon, Sujin v Kim, Da Hye | 1-6,3-6 |
| ITF Women Gyeongsan Qual | 2018/06/11 02:00 | Koike, Satsuki v Miyahara, Mihoki | 6-2,6-2 |
| ITF Women Gyeongsan Qual | 2018/06/10 03:30 | Koike, Satsuki v Lee, Jeongyun | 7-6,6-1 |
| ITF Women Sangju Qual | 2018/06/03 02:00 | Eri Shimizu v Koike, Satsuki | 2-6,7-5,6-3 |
| ITF Women Fukuoka Qual | 2018/05/06 01:00 | Nagi Hanatani v Koike, Satsuki | 6-1,6-4 |
| ITF Women Gifu Qual | 2018/04/29 04:20 | Hiroko Kuwata v Koike, Satsuki | 6-4,6-1 |
| ITF Women Gifu Qual | 2018/04/29 01:00 | Koike, Satsuki v Hasegawa, Mami | 6-1,6-0 |
| ITF Women Osaka Qual | 2018/04/08 03:30 | Koike, Satsuki v Dabin Kim | 2-6,5-7 |
| ITF Women Osaka Qual | 2018/04/07 01:30 | Koike, Satsuki v Furukawa, Suzuka | 6-0,0-6,6-4 |