Celia Cervino Ruiz defeated Yeon Woo Ku 6-2 7-6 in the W15 Castellon 1 quarter-final on clay. The upset overturned the form book — Yeon Woo Ku came in ranked #176, leading the head-to-head 1–0. Celia Cervino Ruiz claimed a first win over Yeon Woo Ku in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2021-11-25 | W15 Lousada 1 | R16 | hard | Yeon Woo Ku | 6-0 6-0 |
Averages over each player's completed matches in the selected window (187 vs 200). ATP, WTA & Challenger.
Each player's serve crossed against the other's return, converted to expected hold of serve. Recent completed matches, ATP, WTA & Challenger. About