Sina Haas defeated Diana Sumova 6-1 6-1 in the Stuttgart Stammheim $10K round of 32 on hard. The upset overturned the form book — Diana Sumova came in leading the head-to-head 1–0. Sina Haas claimed a first win over Diana Sumova in two meetings, narrowing the head-to-head to 1–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2013-07-15 | Darmstadt 25K | Q16 | clay | Diana Sumova | 7-5 6-2 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.