Sakiko Shimizu defeated Maya Kato 4-6 6-1 6-1 in the Hamanako 25K round of 32 on carpet. The upset overturned the form book — Maya Kato came in leading the head-to-head 1–0. Sakiko Shimizu claimed a first win over Maya Kato in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2011-06-06 | Tokyo 10K | R16 | hard | Maya Kato | 6-1 7-5 |