Natsumi Hamamura defeated Akari Inoue 6-2 6-4 in the Karuizawa 25K round of 32 on carpet. The upset overturned the form book — Akari Inoue came in leading the head-to-head 2–0. Natsumi Hamamura claimed a first win over Akari Inoue in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-05-18 | Nagano 25K | R16 | carpet | Akari Inoue | 6-3 2-6 6-2 |
| 2006-09-04 | Kyoto 10K | R32 | carpet | Akari Inoue | 6-3 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.