Maria Sharapova and Kim Clijsters beaten at Wimbledon

Top seed Maria Sharapova and Kim Clijsters were knocked out of Wimbledon in straight sets in the fourth round.

Sharapova had been bidding to become the first player since Serena Williams in 2002 to win the French Open-Wimbledon double in the same year.

But the Russian world number one was beaten 6-4 6-3 by German 15th seed Sabine Lisicki on a chilly Court One.

Clijsters, due to retire after the US Open later this year, lost 6-1 6-1 to German eighth seed Angelique Kerber.

Lisicki, 22, secured victory with her third match point, an ace on her second serve, and will face her compatriot Kerber in the quarter-finals.

Lisicki broke Sharapova's serve three times in the first set and, following a rain delay, once early in the second to clinch victory by the same score she lost to the Russian in last year's semi-finals.

"It's unbelievable. I've beaten Maria Sharapova for the first time," Lisicki told BBC Sport. "I just went for my shots from the first point on.

"She is a fighter but I am a fighter too. I fought to the last point. The last game was tough but I fought it out.

"I'm getting better with each match. This is my favourite tournament. I love it here."

The Russian completed a career Grand Slam by winning at Roland Garros last month, but will lose her number one ranking to either Victoria Azarenka or Agnieszka Radwanska when the new list comes out on Monday.

Sharapova said: "She [Lisicki] did many things better than I did and you have to hand it to her. She played very well. I could have done things differently but not on this particular day."

Clijsters, who has won four Grand Slams but never reached a Wimbledon final, struggled to get her serve into gear and committed a string of unforced errors.

The Belgian survived two match points at 5-0 down in the second set but Eastbourne finalist Kerber soon served out for a comprehensive victory.

Clijsters, who made her Wimbledon debut as a 16-year-old and was a semi-finalist in 2003 and 2006, said the fact it was her last match at the Championships had not entered her thoughts.

"I just had the feeling that there was absolutely nothing I could have done to have won that match," said the former world number one.

"My opponent was better on every level. That was all I was thinking about."

The 29-year-old will play in the Olympics at Wimbledon and then the US Open before retiring for the second and final time, having previously taken two years out to start a family.

"I know that every time I've played here I've given my best, and that's the only thing that I can do," she added.

"I'll never say that I didn't work hard enough or I didn't practise hard enough. I don't think I'll feel sorry about anything when I leave."

In the two other matches in this half of the draw, Polish third seed Radwanska beat Italian qualifier Camila Giorgi 6-2 6-3 and will face 17th seed Maria Kirilenko in the quarter-finals.

Russia's Kirilenko broke twice in the final set to win 6-1 6-7 (6-8) 6-3 in two hours and 20 minutes against China's Shuai Peng.