US Open champion Stosur out of China Open

US Open champion Samantha Stosur was knocked out of the China Open on Tuesday in another upset at the tournament following shock defeats for the women's Wimbledon and French Open champions.

The Australian world number seven lost 7-5, 1-6, 7-5 in the second round to 2005 Beijing champion Maria Kirilenko, following early exits for French Open winner Li Na and Wimbledon champion Petra Kvitova.

Stosur was beaten in her opener last week in Tokyo as she played her first match since beating Serena Williams in last month's US Open final.

Kirilenko broke in the final game to claim the victory, with Stosur saving only one of six break points in a match lasting more than two hours.

Three other women's seeds advanced, with two-time Grand Slam finalist Vera Zvonareva (third seed) of Russia putting out Czech Klara Zakopalova 6-3, 4-6, 6-2 and French number eight seed Marion Bartoli beating American Christina McHale 6-2, 6-1

Russian Anastasia Pavlyuchenkova, seeded 13, defeated Spain's Maria Martinez Sanchez 6-2, 6-3.

In the men's draw, top seed Jo-Wilfried Tsonga, who won the Metz title last month and is bidding to reach the eight-man ATP World Tour Finals, defeated Bulgarian Grigor Dimitrov 7-6 (7/5), 7-5.

Tsonga fired down nine aces and broke Dimitrov twice in their battle lasting just under two hours, beating the Bulgarian for the third time this season.

"It was difficult to play Grigor because he's a really good player," said Tsonga. "For a first round, it was not easy.

"I didn't move really well, I didn't hit the ball really good, but I was on the court with my head and I did it. So I'm really happy to go through this one."

Russian Mikhail Youzhny, returning after a back injury, upset Spanish fourth seed Nicolas Almagro 6-3, 6-2 while China will have a player in the second round after Zhang Ze beat Li Zhe 6-1, 6-3.