Klara Zakopalova of the Czech Republic also advanced, rallying past sixth-seeded Julia Goerges of Germany 3-6, 7-5, 6-1. Zakopalova will face second-seeded Marion Bartoli of France, who downed Roberta Vinci of Italy 4-6, 6-4, 7-6 (2).
“I had to dig deep to raise my game and keep believing in the victory,” Bartoli said. “My strength was to never give in. Even though I sometimes made tactical mistakes, I always tried to find a solution.”
Kerber broke serve three times in the first set and rallied from 3-1 down in the second, clinching the victory when the Russian hit a forehand long for her 33rd unforced error.
“It’s amazing, it’s my first top-five win,” Kerber said. “I knew before the match that I have nothing to lose. So I was going out there and really tried to play from the first point, my best tennis. I’m very happy that I beat her and I’m now in semis.”
“It was a tough day because my opponent played really well,” said Sharapova, who led 4-2 in the first set. “When I did have the opportunities, I just didn’t take them today.
“I wasn’t as aggressive as I would have liked to be against her. She’s someone that also likes to go in and has a good amount of power. And she just used that to her advantage much more than I did.”
Sharapova won their only previous meeting, 6-1, 6-2 in the third round of the Australian Open last month.
“In Australia, that was my first match against her,” said Kerber, a semifinalist at the Hobart International and ASB Classic last month. “I think I was a little bit shocked to play against her because she’s a great player. And here, I was trying to play aggressive and be tough in every point.”
Kerber is part of a new German generation that is blossoming. Five Germans are ranked in the top 50 this season for the first time since February 1996.
“She’s starting to really break through and also being a lefty gives her a bit of an edge as there are not too many,” Sharapova said.
Vinci led 4-1 in the second set and 5-2 in the third. The Italian rifled a backhand pass down the line to save a match point at 6-5 and ultimately force a tiebreaker. But Bartoli won the last four points, firing a forehand winner to convert her second match point.
Zakopalova won seven straight games in sealing the second set and taking a 5-0 lead in the third. She ended the match when the German hit a forehand return long.