Serena, Venus to team up

London - Venus and Serena Williams, John Isner and Andy Roddick were among 12 players named on Tuesday to the US Olympic tennis team for the London Games by the US Tennis Association.

The London Olympic tennis events will be staged from July 28 through August 5 on the grass courts at Wimbledon.

The Williams sisters are unbeaten in Olympic women's doubles and seek a third gold medal after triumphs in 2000 and 2008.

Serena, 30, reached the 2008 Olympic singles quarter-finals. The 13-time Grand Slam champion has four Wimbledon titles and 12 Grand Slam doubles crowns alongside her sister, four of those coming at Wimbledon as well.

Venus 32, becomes the first American tennis player to compete in four Olympics. She won singles gold at Sydney in 2000 and two more with her sister in doubles. Her seven Grand Slam titles include five at Wimbledon.

US women's tennis coach Mary Joe Fernandez also has Christina McHale and Varvara Lepchenko in singles and the Williams sisters plus the World No. 1 tandem of Liezel Huber and Lisa Raymond in doubles.

"I'm honoured to have the opportunity to coach this team at the Olympics and firmly believe that we have a team capable of competing for multiple medals," Fernandez said.

Isner, 2004 Olympian Roddick, Donald Young and Ryan Harrison will play singles on the men's side with the 2008 bronze medal pair of Bob and Mike Bryan set for doubles. Isner and Roddick will also play together in doubles.

"I'm confident that we will be in medal contention in both singles and doubles," said US men's coach Jay Berger.

Two mixed doubles duos from the players already on the squad will be named once all players arrive in London. Mixed doubles will be contested for the first time since the sport returned to the Olympic lineup in 1988.

The 17 medals won by US players since the return in 1988 are more than any other nation has produced.

Isner, 27, makes his Olympic debut at the venue where he won the longest match in tennis history, beating Frenchman Nicolas Mahut 70-68 in the fifth set of a 2010 first-round match lasting 11 hours and five minutes over three days.

Roddick, 29, was a 2004 Olympic quarter-finalist. He won the 2003 US Open and reached the Wimbledon finals three times, including 2009.

Mike and Bob Bryan, 34, have won 11 Grand Slam doubles titles, two of them at Wimbledon.

McHale, 20, and Lepchenko, 26, will make their Olympic debuts. McHale took the bronze last year at the Pan American Games. Lepchenko, an Uzbekistan native who received political asylum in the United States in 2001 and became a citizen in 2011, was one of only two Americans into the round of 16 at this year's French Open.

Huber, 35, competed for South Africa in 2000 and the US in 2008. Her five Grand Slam doubles titles include two at Wimbledon. Raymond, 38, has won six Slam doubles crowns, including Wimbledon in 2001.