Beijing:Roger Federer and Stanislas Wawrinka upset US top seeds Bob and Mike Bryan on Friday to reach the men's doubles final, assuring the Swiss world number one of a first Olympic medal.
Federer, stunned in the singles quarter-finals by James Blake, and Wawrinka ran out 6-2, 6-4 winers in their second match of the night after earlier beating India's Mahesh Bhupathi and Leander Paes.
In the other semi-final, Sweden's Simon Aspelin and Thomas Johansson beat Arnaud Clement and Michael Llodra of France in the longest three-set men's match in Olympic history.
The eventual scoreline of 7-6 (8/6), 4-6, 19-17, played over four hours and 46 minutes, added up to 59 games plus a tie-break.
The previous record of 54 games was set by Australian doubles greats Todd Woodbridge and Mark Woodforde in their Atlanta 1996 semi-final win against Dutch duo Jacco Eltingh and Paul Haarhuis.
Ukraine's Alona Bondarenko and Kateryna Bondarenko reached the women's doubles semis with a 6-1, 3-6, 7-5 win over Italians Flavia Pennetta and Francesca Schiavone.
The Bondarenko sisters will face US siblings and 2000 champions Venus and Serena Williams, who raced through their quarter-final 6-4, 6-0 against Rjussia's Elena Vesnina and Vera Zvonareva.
Twelve-time Grand Slam champion Federer has never won an Olympic medal but finished fourth in the 2000 singles.