Mariana Demichelli Vergara defeated Daniela Seguel 6-7 6-4 6-1 in the Santiago 10K round of 32 on clay. The upset overturned the form book — Daniela Seguel came in leading the head-to-head 1–0. Mariana Demichelli Vergara claimed a first win over Daniela Seguel in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2009-11-02 | Bogota 10K | R32 | clay | Daniela Seguel | 6-2 6-3 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.