Top seed Sharapova stunned by Lisicki

Maria Sharapova's hopes of winning a second Wimbledon title were shattered on Monday as the world number one was comprehensively beaten 6-4, 6-3 by Germany's Sabine Lisicki in the fourth round. 

The world number 15 had top seed Sharapova on the back foot early in the first set, forcing her into a string of uncharacteristic errors, and did not let up until she had gained revenge for her semi-final defeat by the Russian last year.

Lisicki, who had complained about her second-round opponent Bojana Jovanovski's grunting, was forced to endure Sharapova's loud wails, but kept her concentration to break the French Open champion decisively in the 10th game of the first set. 

She broke again early in the second and closed it out, converting her third match point with an ace.

"It is just unbelievable for me, I'm just so happy," Lisicki said after falling to her knees with both fists clenched in celebration. 

"I have lost my three previous meetings with her. I just went for my shots...

"I am a fighter too and I fight to last point. I'm getting better with each match."

The German will play her compatriot Angelique Kerber in the quarter-finals.

Kim Clijsters waved goodbye to Wimbledon on Monday after she was thrashed 6-1, 6-1 by German eighth seed Angelique Kerber at a windswept and chilly All England Club on Monday.

The Belgian, who will be retiring for a second time after this year's U.S. Open, looked like a pale shadow of the player who has won four major titles. She struggled to get her serve into gear and committed a string of unforced errors.

Kerber was in sparkling form and totally dominated the exchanges against crowd favourite Clijsters, who was suffering from an abdominal injury in the leadup to Wimbledon.

Clijsters survived two match points at 5-0 down in the second set but it was a last throw of the dice against the fiercely determined Kerber who served out for victory.

At least one German player is guaranteed a place in the semi-finals after Kerber booked a last-eight date with compatriot Sabine Lisicki.

Defending champion Petra Kvitova came back from a set and a break down to beat Italian Francesca Schiavone 4-6, 7-5, 6-1 in a rain-disrupted fourth-round match at Wimbledon on Monday.

Kvitova, the fourth seed, looked to be in trouble when former French Open champion Schiavone went a set and 2-1 up, taking advantage of a double fault to help her break the Czech.

Kvitova, however, broke straight back and went 6-5 up before light rain began falling on Court Three.

The match continued after a series of stops and starts and Schiavone was clearly unhappy at being told to resume play early in the third set, complaining to no avail that the grass was damp.

As the Italian continued to glower and mutter, Kvitova raced through two breaks of serve to wrap up the set in 39 minutes and will now face former champion Serena Williams.

Roger Federer shook off a back injury to beat Xavier Malisse 7-6, 6-1, 4-6, 6-3 and reach the Wimbledon quarter-finals on Monday.

The six-times champion left Centre Court after the seventh game of the first set for treatment and returned eight minutes later before dropping his serve to trail 5-6.

But the third seed broke back immediately, roared through the tiebreak 7-1 and dominated the second set.

The 31-year-old Malisse, world number 75, broke the Swiss early in the third set and with Federer's movement clearly restricted the underdog pulled a set back.

Federer received more off-court treatment and dropped his serve again at the start of the fourth set but Malisse's game suddenly fell apart and the 16-times grand slam champion wrapped up victory with an ace.

Four-times champion Serena Williams dug deep on Monday to book a place in the Wimbledon quarter-finals, seeing off 'golden-set' challenger Yaroslava Shvedova 6-1, 2-6, 7-5 just in time before the rain came back down at a gloomy All England Club.

Kazakhstan's Shvedova, who became the first player to win a set at a grand slam without dropping a point in the previous round, troubled the American as the dark clouds gathered above Court Two but was undone by a late flurry of pace and power.

Williams, the sixth seed, took just 26 minutes to race to a first set lead. She dominated with her more powerful serve and ground strokes but was made to work much harder from then on as Shvedova found her rhythm.

The American, watched by her sister Venus and her father, went down a break at 4-2 in the second as she started to struggle with her movement.

Shvedova began hitting the lines with a piercing backhand that had Williams flailing and she sealed the set with another screaming effort that sailed past the American.

With Williams's performance so far as temperamental as the British Wimbledon weather, the final set was a much more even contest, both women exchanging blows in lengthening rallies.

Four break points came and went for Williams as Shvedova dug in with some brilliant shots. But the Kazakh was undone by two double faults that put her in trouble and left her 6-5 down.

With light rain now trickling down on court Williams produced a superb lobbed backhand in the final game that had the crowd cheering before a blazing backhand sent Shvedova lunging in vain and sealed victory in just under two hours.

"I felt fine out there I think we both wanted to keep playing because it was so deep into the match," Williams said.

"I'm not tired so I feel good. I feel like I can play so much better than what I have been playing."

Williams, 30, and 13-times grand slam champion, will next face holder Petra Kvitova.