LONDON - United States won the latest battles in their fierce track rivalry with Jamaica on Wednesday while Usain Bolt cruised through to the 200 metres final where he will aim to prove once and for all he is an Olympic "legend".
Bolt goes into Thursday's final seeking to become the first man to win the 100 and 200 at two successive Olympics.
The Jamaican and the training partner he playfully nicknames The Beast, compatriot Yohan Blake, comfortably won their 200 semi-finals with both easing up towards the line.
"He's my good friend and I think it's going to be interesting," Blake told reporters.
Bolt said he was looking forward to the final of his favourite event and would win it "without a doubt".
"I'm never going to say I'm the greatest until I've won the 200. It was all about this, to successfully defend my titles, because this is what's going to make me a legend," he said after his 100 victory in London on Sunday.
Elsewhere on the track on day 13 on Thursday, Kenyan David Rudisha is favourite in the 800 and world champion Christian Taylor and fellow American Will Claye contest the men's triple jump.
Women's world record holder Barbora Spotokova will also have her eye on another javelin gold while American world record holder Ashton Eaton is the man to beat in the decathlon.
The U.S. women's soccer team will have revenge on their minds when they take on Japan, the side they lost to in last year's World Cup final, in the final at Wembley.
The U.S. women's basketball team go for their 40th Olympic win in a row when they play Australia in the semi-finals while Brazil and the U.S. are hoping to set up a repeat of the Beijing women's volleyball gold-medal match by getting past Japan and South Korea respectively.
In the women's handball, holders Norway take on Beijing 2008 bronze medallists South Korea in the first semi-final followed by Spain against debutants Montenegro.
The Americans captured seven of the dozen athletics medals available on Wednesday, with Aries Merritt rocketing to victory in the men's 110 hurdles and Allyson Felix striking gold at her third attempt in the 200.
Brittney Reese registered only two out of six attempts in the long jump but her second leap of 7.12 metres was good enough to win the third U.S. gold of the night.
With Misty May-Treanor and Kerri Walsh picking up their third straight Olympic beach volleyball title in an all-American final, the U.S. lifted their haul of golds to 34 to make up ground on China at the top of the medals table.
The Chinese won in women's taekwondo and the men's team table tennis - completing a second successive Olympic clean sweep in that sport - to advance to 36 golds.
"The guys were talking about closing the gap on China. We will show we are the best track and field nation in the world," said Jason Richardson, runner-up to Merritt in the 110 hurdles.
Elsewhere, Hungary won the men's and women's canoeing titles, Spain took a gold in men's taekwondo and Steve Guerdat of Switzerland won the individual show jumping crown.
French and Spanish basketball players nearly came to blows while Italy's men knocked out the U.S. holders in volleyball and Hungary in water polo.
Felix, a silver medallist at the last two Olympics, lengthened her stride on the home straight of the 200 final to beat Shelly-Ann Fraser-Pryce, the Jamaican winner of the 100.
"It's been a long time coming. I am so overjoyed," said Felix who was runner-up to Jamaican Veronica Campbell-Brown in 2004 and 2008 and lost her world title to her last year.
The men's hurdles was also a U.S.-Caribbean affair, with Jamaican Hansle Parchment taking bronze behind Americans Merritt and Richardson.
Russia's Natalya Antyukh just held on at the line to beat American Lashinda Demus in the women's 400 hurdles.
American Ashton Eaton was also in front at the halfway stage of the decathlon, ahead of team mate Trey Hardee and Damian Warner of Canada.
Earlier on Wednesday, Sarah Attar became the first woman from Saudi Arabia to compete in the Olympic athletics, coming last in an 800 heat she ran wearing a white head cover.
In the boxing ring, where women are competing at the Olympics for the first time, Ireland's Katie Taylor beat a Tajik opponent to set up a lightweight final on Thursday against Russia's Sofya Ochigava.
In the middleweight final, 17-year-old Claressa Shields of the U.S. will face another Russian, Nadezhda Torlopova, who at 33 is nearly twice her age.
In basketball, Spain broke open a fierce defensive battle in the final minute to beat France 66-59 and reach the semi-finals in a bad-tempered contest that threatened to turn into a brawl.
"Everybody wants to fight for those medals. Sometimes it gets a little out of hand because emotions get involved. Nobody got hurt, that's the most important thing," Spain's Marc Gasol said.