Natsumi Hamamura defeated Jin A Lee 6-4 6-4 in the Karuizawa 25K qualifying round on carpet. The upset overturned the form book — Jin A Lee came in leading the head-to-head 1–0. Natsumi Hamamura claimed a first win over Jin A Lee in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2010-08-02 | Beijing 75K | R16 | hard | Jin A Lee | 6-3 6-3 |