Vilmarie Castellvi defeated Clarisa Fernandez 1-6 6-1 6-3 in the San Luis Potosi 1 25K qualifying round on clay. The upset overturned the form book — Clarisa Fernandez came in leading the head-to-head 1–0. Vilmarie Castellvi claimed a first win over Clarisa Fernandez in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2006-10-09 | San Francisco CA 50K | QF | hard | Clarisa Fernandez | 7-6(2) 3-6 7-5 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.