Australian Open champ Kerber reaches Charleston quarterfinal

CHARLESTON, S.C. (AP) Australian Open champion Angelique Kerber advanced to the quarterfinals with a 6-2, 6-2 victory over Slovakia's Kristina Kucova at the Volvo Car Open on Thursday.

Kerber is the defending champion after winning the title in last year's Family Circle Cup. The second-ranked German star was not her best, but good enough to put away Kucova, who is ranked No. 142. Kerber broke her opponent's serve seven times, including the final game.

No. 3 seed Venus Williams, No. 5 Sara Errani and No. 7 Sloane Stephens are playing later Thursday.

Kerber needed a third-set tiebreaker to win her opening match at the Volvo on Tuesday night. She quickly gained control over Kucova and won 10 of the final 13 games.