Joanna Sakowicz Kostecka defeated Libuse Prusova 7-5 6-4 in the Pruhonice 25K round of 16 on hard. The upset overturned the form book — Libuse Prusova came in leading the head-to-head 1–0. Joanna Sakowicz Kostecka claimed a first win over Libuse Prusova in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2004-12-13 | Valasske Mezirici 25K | QF | hard | Libuse Prusova | 6-4 6-4 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.