Mayumi Yamamoto defeated Mari Tanaka 6-3 6-3 in the Tsukuba 25K round of 32 on hard. The upset overturned the form book — Mari Tanaka came in leading the head-to-head 2–0. Mayumi Yamamoto claimed a first win over Mari Tanaka in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2007-08-27 | Saitama 10K | QF | hard | Mari Tanaka | 6-1 1-6 6-3 |
| 2007-08-13 | Tokyo 10K | R16 | carpet | Mari Tanaka | 6-2 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.