Olympics tennis: Roger Federer & Stanislas Wawrinka out of doubles

Defending champions Roger Federer and Stanislas Wawrinka of Switzerland have crashed out of the Olympic men's doubles at Wimbledon.

The sixth seeds lost to Israeli pair Jonathan Elrich and Andy Ram 1-6 7-6 (7-5) 6-3 in the second round.

Federer had better luck in the men's singles, beating Uzbekistan's Denis Istomin 7-5 6-3 after two rain delays.

Second seed Novak Djokovic made the last eight by beating former Wimbledon champion Lleyton Hewitt 4-6 7-5 6-1.

He will face Jo-Wilfried Tsonga have the Frenchman beat Spain's Feliciano Lopez 7-6 6-4.

World number one Federer said: "I'm disappointed but overall I'm feeling good. It's obviously a whole different feeling out there because of the Olympic Games.

"Best-of-three-set tennis is very fast. In the doubles, even more so. I think we played two good doubles and I'm playing well in the singles."

In the women's singles, Venus Williams blew a lead in each set as she lost her last-16 women's singles match to Angelique Kerber of Germany.

Bidding for a record fourth tennis gold, she led 5-1 in the first set and 3-1 in the second but lost both on tie-breaks in a 7-6 (7-5) 7-6 (7-5) defeat.

Her sister, Serena Williams, reached the last eight along with world number one Victoria Azarenka, from Belarus.

Maria Sharapova beat Sabine Lisicki, of, Germany 6-7 (8), 6-4, 6-3 and will face Kim Clijsters in the quarter-finals after the Belgian overcame Ana Ivanovic, of Serbia 6-3 6-4.

In the men's doubles, Czech fifth seeds Tomas Berdych and Radek Stepanek, and Marcelo Melo and Bruno Soares, of Brazil, set two Olympic records in an epic encounter.

Melo and Soares won 1-6 6-4 24-22 in four hours and 21 minutes - the most games ever in a doubles match (63 games) and a single set (46).

Watch Serena Williams's match against Victoria Azarenka