Sakiko Shimizu defeated Mari Tanaka 7-6 6-4 in the Komoro 10K round of 32 on clay. The upset overturned the form book — Mari Tanaka came in leading the head-to-head 2–0. Sakiko Shimizu claimed a first win over Mari Tanaka in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2011-06-27 | Pattaya 10K | R32 | hard | Mari Tanaka | 6-4 7-6(9) |
| 2007-08-13 | Tokyo 10K | QF | carpet | Mari Tanaka | 6-4 6-0 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.