Maria Sharapova won a marathon three-setter against compatriot Maria Kirilenko to advance to the semifinals of the BNP Paribas Open at Indian Wells.
Sharapova came back from a set down to grind out a 3-6, 7-5, 6-4 win in three hours Thursday and set up a semifinal against Ana Ivanovic.
It was Sharapova's first serious challenge of the tournament so far, having sauntered through the openening rounds with one walkover and two straight-sets victories.
"She did start very well, but also it was a poor start from my end," Sharapova said in comments carried by the tournament website.
"I was just trying to find my rhythm a little bit on everything, movement- and playing-wise, and a little by little I started feeling better. Towards the end I really got my groove back, so that was good."
Her opponent for Friday's semifinal, Ivanovic, had a more straightforward win over Marion Bartoli of France, coming through 6-3, 6-4.
Australian Open winner Victoria Azarenka meets Germany's Angelique Kerber in the other semifinal.
