Top-seeded Angelique Kerber dropped a set before beating local wild card Cornelia Lister 2-6, 6-4, 6-2 on Wednesday in the second round of the Stockholm Open.

The second-ranked German, who lost to Serena Williams in the Wimbledon final earlier this month, struggled to adjust to the change of surface on the clay in Bastad.

"It was difficult, because this was my first match after grass on clay again," said Kerber, who was returning to Bastad for the first time in five years. "The first matches are always a little bit tricky for me."

The left-handed Australian Open champion suffered a left elbow injury early in the match that taxed her normally powerful strokes. The 22-year-old Swede was quick to capitalize on Kerber's difficulties, breaking her serve three times in the first set to get an early lead, but Kerber bounced back after receiving treatment during a medical timeout.

In other games, second-seeded Sara Errani of Italy defeated Switzerland's Viktorija Golubic 7-6 (6), 6-1, and Karin Knapp of Italy beat 2014 champion Mona Barthel of Germany 6-0, 7-5.

Errani lined up a quarterfinal against Czech qualifier Katerina Siniakova, who ousted fifth-seeded Anna Karolina Schmiedlova of Slovakia 6-3, 4-6, 6-4.

Sixth-seeded Laura Siegemund of Germany beat Lucie Hradecka of the Czech Republic 7-5, 7-6 (4) to advance to the last eight.