JOIN USPetrova shocks Serena; Nadal fights past Blake
The American, who will retake the number one spot next week, lost 6-4, 3-6, 7-6 in a hard fought contest against the Russian 13th seed to join her third seeded sister Venus and top seed Dinara Safina in exiting the tournament.
Men's top seed Rafa Nadal was delighted with his form and fitness after earlier negotiating a tricky second round tie against American James Blake to reach the last eight.
Nadal, playing his first tournament since picking up an abdominal injury at the US Open, was not at his rampaging best but certainly proved his fitness by outlasting Blake 7-5, 6-7, 6-3.
Blake, ranked 24th after missing part of the season through injury, hit the ball low and hard throughout the match but errors on key points allowed the Spaniard to tie up their career head-to-head at 3-3.
The New Yorker refused to back down throughout the contest and saved a match point before winning the second set in a tiebreak, only to hand the world number two a 5-3 lead with a double fault in the decider.
Former world number one Safin, who plans to retire at the end of the season, proved there was still life in his injury-wracked body with a 6-3, 6-4 win over seventh seed Fernando Gonzalez.
In the women's draw, the third round proved a step too far for China's world number 226 Zhang Shuai -- the lowest ranked player to beat a world number one when she upset Safina in the second round.
The wildcard went down 6-1, 6-4 to France's Marion Bartoli, who will next play Vera Zvonareva after the Russian seventh seed outlasted 10th seeded Italian Flavia Pennetta 6-3, 5-7, 7-5.
Tsonga in quarters
Jo-Wilfried Tsonga outmuscled fellow Frenchman Richard Gasquet 4-6, 6-2, 6-2 to reach the quarterfinals of the Japan Open on Thursday.
Former world number one Lleyton Hewitt also advanced to the quarters, the eighth seed beating Fabrice Santoro 3-6, 6-3, 6-1. Hewitt plays Frenchman Edouard Roger-Vasselin next after the world number 189 followed his shock win over top seed Juan Martin del Potro by beating Austrian Juergen Melzer 4-6, 6-2, 6-3. Fifth seed Tomas Berdych showed the kind of form that swept him to last year's Tokyo title, the Czech overpowering Germany's Andreas Beck 6-4, 6-1.