Polona Hercog defeated Katerina Siniakova 3-6 7-5 6-2 in the Stuttgart qualifying round of 32 on clay. The upset overturned the form book — Katerina Siniakova came in ranked #55, leading the head-to-head 1–0. Polona Hercog claimed a first win over Katerina Siniakova in two meetings, levelling the head-to-head at 1–1.
Hercog P. came through in three sets.
Hercog P. and Siniakova K. faced 4 of the same opponents in the last 12 months. Hercog P. went 1–3 (25%) against them, Siniakova K. 3–1 (75%). Siniakova K. came out better against 2 of 4 comparable opponents, Hercog P. against 0.
Only 4 common opponents — small sample, treat as indicative.
Polona Hercog beat Katerina Siniakova 3-6 7-5 6-2. Umpiry, "Polona Hercog vs Katerina Siniakova — Stuttgart Qualifying Round of 32", https://umpiry.com/match/2016-04-16/hercog-vs-siniakova-stuttgart-q32?utm_source=cite (as of 16 April 2016).