Estefania Balda Alvarez defeated Leticia Sobral 6-3 6-3 in the Asuncion 10K round of 16 on clay. The upset overturned the form book — Leticia Sobral came in leading the head-to-head 1–0. Estefania Balda Alvarez claimed a first win over Leticia Sobral in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2004-08-16 | Guayaquil 10K | R32 | hard | Leticia Sobral | 6-2 4-6 6-3 |