SERENA Williams was knocked out of Wimbledon.

Andy Murray will have to be carried out.

The overwhelming favourite for the women's title was last night preparing for an unexpected flight back to the USA after she was beaten by Sabine Lisicki 6-2, 1-6, 6-4 but Murray is now set for a quarter-final with Fernando Verdasco of Spain after defeating Mikhail Youzhny of Russia 6-4, 7-6 (5), 6-1 despite clutching his back on several occasions during a tough match.

Murray withdrew from the French Open citing a back injury but he said last night he will continue at Wimbledon whatever the level of pain.

"I wouldn't stop," he said. "Now that I'm playing, there's no chance I would stop, I mean, unless I couldn't hold the racket."

Murray did not attend his press conference until two hours after the defeat of Youzhny, prompting fears that his back injury had returned.

He said of the delay: 'I need to make sure I do all the right things, like ice bathing, having my massage, and taking care of my body. Obviously, a few weeks ago, I missed the French Open. I don't want it to be a case of things creeping back up on me. I want to take care of my body. It's my main priority this tournament. "

He conceded he had received extra treatment last night but added: "There's no cause for concern. My back is what it is. It's felt way, way better than it was a few weeks ago."

Youzhny admitted he was surprised the spectators were not louder in support of Murray and also felt his opponent lost focus in the second set. The Scot conceded that was partially true, saying: "Maybe a little bit. That's the thing with grass-court tennis. I missed a couple of shots in the tape, I lost a few challenges, he hit a few balls on the line. It turned around pretty quickly. But luckily I managed to get it back in time."

Murray, meanwhile, was dismissive of claims that he now had an easy run to a potential final with Novak Djokovic, who defeated Tommy Haas in three sets last night.

He pointed out that Williams had been on a 34-match winning streak before her defeat to Lisicki, adding: "When those sort of results can happen to a player as good as her, there's absolutely no reason why it can't happen to me. That's why I'm not getting ahead of myself, and no one else should."

Williams blamed her downfall on a lack of aggression, adding: "I just definitely feel like I could have went for it a little more on some of the shots. I definitely should have made some shots."

She was also generous about the quality of her opponent. "Sabine always plays really well at Wimbledon, so I knew going in it would be a tough match," she said, highlighting the German's formidable serve.

Williams, who started the tournament embroiled in a spat with rival Maria Sharapova, was asked yesterday about "unflattering" remarks made by Annabel Croft, the former British tennis player. She described Williams as having a "huge backside" during a corporate lunch at Wimbledon.

Questioned about whether this remark bothered her, the world No.1 said: "No, I'm fine. Thanks for asking, though."

She added: "I don't know exactly what she said. I don't care to know what she said."

Lisicki, the world No.24, came to the match with the seemingly invincible Williams with a "good omen" on her side. She has beaten the French Open champion at Wimbledon in 2009, 2011, 2012 and now 2013. She missed the 2010 tournament through injury.

She admitted that statistic gave her "a little more energy".

In a day of controversy and defeat for Williams, however, the bottom line is that she was beaten by the better player on the day.