Geraldine Aizenberg defeated Sabrina Valenti 7-5 6-4 in the Buenos Aires 10K round of 32 on clay. The upset overturned the form book — Sabrina Valenti came in leading the head-to-head 1–0, but Geraldine Aizenberg had been the form player, winning 7 of their last 10 on clay. Geraldine Aizenberg claimed a first win over Sabrina Valenti in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 1999-09-13 | Buenos Aires 25K | R32 | clay | Sabrina Valenti | 6-2 7-6 |