Ayumi Oka defeated Makiho Kozawa 6-3 6-2 in the Noto 25K round of 32 on carpet. The upset overturned the form book — Makiho Kozawa came in leading the head-to-head 3–0. Ayumi Oka claimed a first win over Makiho Kozawa in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2011-09-12 | Kyoto 10K | QF | carpet | Makiho Kozawa | 5-6 |
| 2011-05-30 | Mie 10K | R32 | carpet | Makiho Kozawa | 7-6(3) 6-2 |
| 2010-08-02 | Niigata 10K | R32 | carpet | Makiho Kozawa | 6-7(2) 6-2 6-2 |