Seiko Okamoto defeated Antonia Matic 7-5 3-6 6-3 in the Nuriootpa 25K round of 32 on hard. The upset overturned the form book — Antonia Matic came in leading the head-to-head 1–0. Seiko Okamoto claimed a first win over Antonia Matic in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2003-12-01 | Changsha 50K | R32 | hard | Antonia Matic | 0-6 6-2 6-3 |