Yurina Koshino defeated Seiko Okamoto 4-6 6-4 6-3 in the Kofu 10K round of 16 on hard. The upset overturned the form book — Seiko Okamoto came in leading the head-to-head 1–0. Yurina Koshino claimed a first win over Seiko Okamoto in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2007-05-28 | Gunma 25K | R16 | carpet | Seiko Okamoto | 5-7 6-3 6-3 |