French Open champion Sharapova has played seven-and-a-half hours in her three matches here on clay, but comfortably took the first set with two breaks, before Kerber returned the compliment in the second.
The third-set was a battle royal as the pair shared five breaks and third-seed Kerber refused to yield until the final phase of the 2hrs, 16mins match.
Sania-Bethanie in semis
Sania Mirza and Bethanie Mattek-Sands defeated Liezel Huber and Janette Husarova to enter the women’s doubles semi-final here.
The Indo-American pair got past the American-Slovak combination 7-5, 6-4 in the quarter-finals. They next play Angelique Kerber and Andrea Petkovic.