Diana Sumova defeated Zuzana Zalabska 6-2 6-3 in the Piestany 10K round of 16 on clay. The upset overturned the form book — Zuzana Zalabska came in leading the head-to-head 3–0. Diana Sumova claimed a first win over Zuzana Zalabska in four meetings, narrowing the head-to-head to 3–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2015-07-20 | Bad Waltersdorf $10K | F | clay | Zuzana Zalabska | 5-7 7-5 6-1 |
| 2014-09-01 | Prague 10K | R32 | clay | Zuzana Zalabska | 3-6 6-1 6-3 |
| 2010-08-02 | Vienna 10K | R32 | clay | Zuzana Zalabska | 6-2 7-6(3) |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.