Angelique Kerber defeated her longtime friend and compatriot Andrea Petkovic in the second round of the Porsche Tennis Grand Prix in their 12th career meeting.
The 2015 and 2016 Stuttgart champion Kerber confidently opened the encounter with a break and even though Petkovic broke back right away, when she wasted a chance to go up 3-1, the rest of the set was dominated by her fifth-seeded opponent.
After a close battle in the first half of the second set, wildcard Petkovic double-faulted and handed Kerber a break in the crucial seventh game.