Kerber finished off all five of her break chances in a 6-4, 6-4 win over Sharapova. It was the second time they'd played. Sharapova dropped just three games in an Australian Open meeting earlier this year.
But Kerber improved on that result by fighting off eight of the 11 break points Sharapova had. Kerber took 47 percent of the points off the Russian's serve and advanced to the semifinals with three breaks in the first set and two in the second.
Second-seeded Marion Bartoli escaped a third-set tiebreaker in beating No. 7-seeded Roberta Vinci 6-4, 4-6, 7-6 (7-2). Each player dropped serve six times in the 2-hour, 40-minute match. That included a pair of breaks each in the final set before Bartoli took the tiebreaker.
Klara Zakopalova ousted sixth-seeded Julia Goerges 3-6, 7-5, 6-1, losing only 18 points in the third set. Yanina Wickmayer and Mona Barthel slugged it out for more than 2 1/2 hours before Wickmayer emerged with a 6-4, 6-7 (3-7), 6-3 victory.
Bartoli goes against Zakopalova in Saturday's semifinals. They've split their four career meetings. Wickmayer is 1-0 against Kerber, her semifinal opponent.