Guillermina Naya defeated Milagros Montero 6-1 4-6 6-4 in the El Trebol 10K q16 on clay. The upset overturned the form book — Milagros Montero came in leading the head-to-head 1–0, but Guillermina Naya had been the form player, winning 6 of their last 9 on clay. Guillermina Naya claimed a first win over Milagros Montero in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2013-10-28 | Buenos Aires 10K | R32 | clay | Milagros Montero | 6-1 7-6(6) |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.