Former world number one Ana Ivanovic crashed out of the China Open on Friday, beaten by home favourite Zheng Jie in a marathon quarterfinal clash.

Ivanovic, the second seed in China, lost 7-6 (7-4), 2-6, 6-4 to her Wimbledon conqueror in a match lasting almost three hours.

The French Open champion had fought her way back into the match, taking the second set despite an error-strewn display, but she could not establish control.

China's world number 30 was quickly into her stride in the third set, breaking the Ivanovic serve in the first game. Despite further breaks for both players, the tenacious Zheng held her nerve to take the decider.

Earlier, the Serbian world number four had wasted two chances to serve for the first set at 5-4 and 6-5.

Ivanovic said Zheng was a tough opponent, but she was upbeat about her own game and said she could now give "100 percent" after recovering from injury.

"She was playing really well. My first serve wasn't going as well as I'd hoped for. I think that was the biggest difference," Ivanovic said, adding she had not been aggressive enough with her returns.

"I feel this tournament, yesterday and today, I played probably some of my best matches since the French Open and that's definitely a positive sign for me," she said.

Zheng shocked Ivanovic at Wimbledon, beating the then top seed in the third round before going on to reach the semifinals.

Ivanovic is part of a group of players behind current number one Serena Williams chasing the top ranking, which also includes the top seed in China, Jelena Jankovic.

But she has had a poor run, including her early exit at Wimbledon and a second round defeat at the US Open, and has also been hit by injuries.

Zheng's win means she has matched the best-ever performance by a Chinese player at this tournament: Peng Shuai also reached the semifinal in 2006.

Elsewhere on quarterfinals day in Beijing, men's sixth seed Tommy Robredo was beaten convincingly 6-4, 6-1 by Israel's world number 92 Dudi Sela, who put out top seed David Ferrer in the previous round.

In other matches, Russia's Vera Zvonareva beat Anabel Medina Garrigues of Spain, 6-0, 6-1 in just 51 minutes and Svetlana Kuznetsova beat Dominika Cibulkova 6-2, 6-4.

Jankovic plays Daniela Hantuchova in an evening match here, followed by men's second seed Andy Roddick against Spain's former world number one, Juan Carlos Ferrero.

AFP