Ana Ivanovic, of all people, defeated defending champion Caroline Wozniacki in the 4th round of the BNP Paribas Open last night. Ivanovic, whose career has been all over the place since she won the French Open in 2008, beat Wozniacki 6-3, 6-2. Wozniacki will now fall out of the top five, and Ivanovic will now play Marion Bartoli in the Indian Wells quarterfinals.
Nadia Petrova's new-found success didn't last, though she fought very hard against countrywoman Maria Kirilenko, breaking her both times that she served for the match in the second set. Kirilenko's 6-1, 5-7, 6-2 victory gives her a quarterfinal match against yet another countrywoman, Maria Sharapova.
If there was a "player of the day" yesterday, though, it had to be Angelique Kerber, who came back from 1-4 in the third round and saved three match points against Christina McHale. Kerber won 6-3, 3-6, 7-6. In the match before that one, she came back from 1-5 down and saved two match points against Sloane Stephens. At this point, I suspect that mental fatigue may be Kerber's worst problem; she'll have a chance to tough it out again against Li Na in the quarterfinals.
The remaining quarterfinal features top seed Victoria Azarenka playing once more against Agnieszka Radwanska. There's a lot we can read into this match. Radwankska is 3-8 against Azarenka, and recently, she has been very critical of Azarenka's on-court behaviors. It's not unreasonable to suggest there may be some tension in the air (though it pales when compared to an upcoming Indian Wells ATP 4th round contest).