Li Na was 2-5 down in the third set against Ana Ivanovic today, but often, a situation like that makes the Chinese star especially dangerous. She won the match 3-6, 6-1, 7-6. Once Li sent the third set into a tiebreak, she raced ahead, but Ivanovic caught up to make it 5-all, suggesting perhaps another momentum swing. It wasn't to be, however, as Li won the next two points.
5th seed Sara Errani beat Alize Cornet 7-5, 7-6. Errani had a match point at 5-2, but Cornet saved it, and went on to construct a set point at 6-5. Errani squeaked by, though, in straight sets.
Agnieszka Radwanska wasn't at her best today, but defeated Sloane Stephens in straight sets. Marion Bartoli retired with an abdominal injury, sending Washington, DC champion Magdalena Rybarikova into the quarterfinals. Serena Williams beat Kirsten Flipkens, Sorana Cirstea continued her good form against Jelena Jankovic, and Petra Kvitova defeated Carlsbad champion Sam Stosur 6-3, 6-3.
Kvitova was broken when she served for the match at 5-2, double-faulting three times in one game. The 2011 Wimbledon champion got her first serve in 74% of the time, and won with 75% of those serves. She saved 10 of 11 break points.
Stanford champion Dominika Cibulkova broke her long losing streak against Roberta Vinci, defeating the Italian player 6-3, 7-6 in an entertaining match.
Here is the quarterfinal draw:
Serena Williams (1) vs. Magdalena Rybarikova
Agnieszka Radwanska (3) vs. Sara Errani (5)
Dominika Cibulkova vs. Li Na (4)
Petra Kvitova (6) vs. Sorana Cirstea
In doubles, Daniela Hantuchova and Martina Hingis were defeated 6-2, 6-4 by Julia Goerges and Barbora Zahlavova Strycova.