Seiko Okamoto defeated Mi Yoo 6-0 7-5 in the Sutama 25K qualifying round on clay. The result followed the form book — Seiko Okamoto came in leading the head-to-head 2–1. Seiko Okamoto extended the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2007-07-09 | Miyazaki 25K | R32 | carpet | Mi Yoo | 6-3 6-1 |
| 2006-10-23 | Hamanako 25K | R16 | carpet | Seiko Okamoto | 6-1 6-3 |
| 2005-05-16 | Changwon 25K | QF | hard | Seiko Okamoto | 6-3 6-1 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.