Tennis: Sharapova crashes out, Serena, Kvitova survive

World number one Maria Sharapova crashed out of Wimbledon on Monday, while four-time winner Serena Williams and defending champion Petra Kvitova survived major scares to reach the quarter-finals.

Sharapova had been a finalist in three of the last four Grand Slams, and arrived at Wimbledon on a high after winning the French Open for the first time last month.

But the top seed came back down to earth with a bump on Court One as German 15th seed Sabine Lisicki avenged last year's Wimbledon semi-final defeat against the Russian with a 6-4, 6-3 fourth round victory.

"She did many things better than I did and you have to hand it to her," said Sharapova.

"She played very well. I could have done things differently but not on this particular day."

Lisicki had lost in the first round of her last four tournaments, but she has hit form at the right time and the 22-year-old's reward is a last eight meeting with compatriot and eighth seed Angelique Kerber.

"It's just unbelievable. I'm so happy. I had lost the last three meetings with her, so it's nice to finally win one," Lisicki said.

"I just went for my shots out there. I felt great, it's my favourite tournament.

"I'm fighter and I fight to the last game. I think I'm getting better with each match."

Kerber demolished Kim Clijsters 6-1, 6-1 to reach the quarter-finals for the first time.

Such a humbling defeat was a cruel way for Belgium's Clijsters to say her Wimbledon farewell as the four-time Grand Slam winner prepares to retire after the US Open.

American sixth seed Williams narrowly avoided the same fate as Sharapova as she dug deep to defeat Yaroslava Shvedova 6-1, 2-6, 7-5 on Court Two.

Serena looked set to cruise through as she took the first set in emphatic fashion, but Kazakh wildcard Shvedova has been in superb form, winning all 24 points and dropping none in a Golden Set against Sara Errani in the previous round, and she responded impressively to force the American to a final set.

Williams, also taken to three sets by Zheng Jie in the previous round, showed why she is a 13-time Grand Slam champion as she finally subdued her gritty opponent to set up a fascinating last eight clash with Kvitova.

"Drama again! I love the drama." Serena said. "I knew the whole time I could play better, but I feel fine. I'm not tired.

"I feel it's going good. The bottom line is I can play so much better than I am. If I couldn't do better that would be a problem. You know me, I'm never satisfied."

Kvitova, who defeated Sharapova in last year's Wimbledon final to clinch her first Grand Slam title, had romped through the first week, dropping just 13 games.

But she had cause for concern in a 4-6, 7-5, 6-1 win over Italian 24th seed Francesca Schiavone.

Schiavone, a former French Open champion, was in control after taking the first set, but lost her cool when the match was allowed to continue despite rain causing both players to slip.

Kvitova, 22, took full advantage, snatching the second set and then sweeping to victory in the decider to book her place in the last eight for the third time.

Unseeded Austrian Tamira Paszek, winner of the grasscourt event at Eastbourne two weeks ago, beat Italy's Roberto Vinci, the 23rd seed, 6-2, 6-2 to book her place in the quarter-finals for the second successive year.

Paszek, who shocked former world number one Carolone Wozniacki in the first round, will play second seed Victoria Azarenka or Ana Ivanovic in the last eight.

Polish third seed Agnieszka Radwanska, twice a quarter-finalist, completed a bad day for Italian tennis as she cruised to a 6-2, 6-3 win over qualifier Camila Giorgi.

Radwanska has never been past the last eight at a major, but can end that barren sequence with a win over 17th seed Maria Kirilenko or China's Peng Shuai.