Two-time defending champion Maria Sharapova needed eight match points to put away top-seeded Agnieszka Radwanska 6-4, 6-3 for a place in the Porsche Grand Prix semifinals on Friday.
Sharapova has won 11 consecutive matches on Stuttgart's indoor clay.
Radwanska played her best tennis in the penultimate game, when she fought off six match points and finally broke Sharapova's serve.
But Radwanska could not keep the momentum and Sharapova's forehand winner down the line gave her two more match points. Sharapova wasted the first with a wild forehand that was both long and wide, but then nailed a forehand winner to the corner to end the match.
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