Ivanovic stays calm to edge past Williams

In an error-strewn encounter, the fourth seed from Serbia recovered from 3-0 down in the second set to claim her first win in five meetings with Williams and set up a semi-final against Slovakia's Daniela Hantuchova.

"It's amazing and I'm just so thrilled," said Ivanovic after winning 7-6, 6-4.

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"We had a lot of really long points and Venus is an amazing competitor."

Neither player was at their best in a first set that saw six service breaks and Williams, who wore heavy strapping on her left thigh, seemed to be struggling to get her usual power on serve.

The American did hit back to force a tie-break, only to lose it 7-3.

Wimbledon champion Williams, runner-up here in 2003, rallied strongly at the start of the second but lost five of the next six games to go out of the tournament.

"I don't like that tape, I don't like wearing it," Williams said. "But I can't blame my loss on that. I think that she just played some good tennis. I didn't win. I would have liked it to be different but, unfortunately, I don't have a time machine, so I cannot reverse this loss.

"I think she's definitely improved on everything in her game."

Ivanovic, who reached her first Grand Slam final at the French Open last year, said she expected a hard match against Hantuchova, who beat Polish teenager Agnieszka Radwanska 6-2, 6-2.

"She's definitely on a roll, she's playing some great tennis here," said Ivanovic.

"It's going to be a very hard match, but it is a great chance for both of us."