By John Stonestreet

LONDON (Reuters) - Australian Open champion Angelique Kerber ground out a 7-6(11) 6-1 win over unseeded fellow German Carina Witthoeft at Wimbledon on Saturday in a third-round contest high on drama but variable in quality.

Against a now familiar backdrop of showery weather, fourth seed Kerber, an All England Club semi-finalist in 2012, began the brighter against her 21-year-old opponent, who she beat 6-0 6-0 when they met at the same venue this time last year.

But both women struggled to cope with a gusting wind in a dramatic first set lasting exactly an hour and featuring six breaks of serve.

Kerber, 28, plowed numerous groundstrokes into the net while Witthoeft often hit long and was plagued by an inconsistent serve, making eight double faults overall.

The higher-ranked player, who upset the odds against Serena Williams to win her maiden grand slam title in Melbourne in January, looked to have blown her chances of pulling ahead when she let four consecutive first-set points slip away in the tiebreak.

But with neither woman able to make the decisive play, Kerber won the breaker 13-11 when Witthoeft hit another backhand beyond the baseline.

Notwithstanding two rain interruptions, the second set was smoother sailing for Kerber, who broke in the second game and again, on her third break point, in the sixth before serving out the match to 30.

In the fourth round, Kerber will face the winner of the match between Japan's Misaki Doi and Germany's Anna-Lena Friedsam.

(Editing by Ed Osmond)