Chiaki Okadaue defeated Akiko Yonemura 7-6 6-4 in the Kurume 50K qualifying round of 16 on grass. The upset overturned the form book — Akiko Yonemura came in leading the head-to-head 7–0. Chiaki Okadaue claimed a first win over Akiko Yonemura in eight meetings, narrowing the head-to-head to 7–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2013-06-17 | Tokyo 10K | QF | hard | Akiko Yonemura | 6-2 6-4 |
| 2011-05-02 | Fukuoka 50K | R32 | grass | Akiko Yonemura | 6-1 2-1 |
| 2009-09-07 | Noto 25K | R32 | carpet | Akiko Yonemura | 6-2 4-6 7-5 |
| 2008-10-13 | Makinohara 25K | R32 | carpet | Akiko Yonemura | 6-3 6-3 |
| 2007-05-28 | Gunma 25K | R16 | carpet | Akiko Yonemura | 6-0 6-2 |
| 2007-05-21 | Nagano 25K | R32 | carpet | Akiko Yonemura | 2-6 7-5 6-4 |
| 2006-05-29 | Gunma 25K | QF | carpet | Akiko Yonemura | 6-2 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.