Andrea Petkovic defeated Mona Barthel 6-2 6-2 in the Washington round of 16 on hard.
Petkovic A. took it in straight sets.
Petkovic A. and Barthel M. faced 7 of the same opponents in the last 12 months. Petkovic A. went 5–3 (63%) against them, Barthel M. 4–3 (57%). Results against comparable opponents are close (2 : 1 better-results split).
Andrea Petkovic beat Mona Barthel 6-2 6-2. Umpiry, "Andrea Petkovic vs Mona Barthel — Washington Round of 16", https://umpiry.com/match/2013-07-29/barthel-vs-petkovic-washington-r16?utm_source=cite (as of 29 July 2013).