Justin Gatlin stormed to victory in the final of the men's 100m final in a time of 9.85 seconds to steal the headlines on day nine of the Games. The 22-year-old American flew out of the blocks to outclass former champion Maurice Greene, who finished third.
Portugal's Francis Obikwelu grabbed the silver, edged out of the top spot by just one-hundredth of a second.
But it was a miserable day for Britain's athletes as Paula Radcliffe's bid for a marathon medal ended when she pulled out in the closing stages of the event.
She had fallen one minute off the pace after 23 miles and was fourth before she stopped and burst into tears.
The race, run in searing heat, was won by Japan's Mizuki Noguchi in a time of two hours 26 minutes and 20 seconds, ahead of Kenyan Catherine Ndereba.
Phillips Idowu had a dire time in the triple jump and is out of the final after three no jumps, while Lee McConnell, Donna Fraser and Christine Ohurougu all failed to reach the women's 400m final.
There was brighter British news as Michael East booked his place in the final of the 1500m.
Sweden dominated the field events on Sunday, Stefan Holm leaping to high jump gold with a best of 2.36m, while countryman Christian Olsson's leap of 17.79m was enough for triple jump gold.
But there was a massive sprint shock when American Gail Devers pulled up before the first hurdle in her heat with a calf injury.
Elsewhere, Team GB were guaranteed at least a silver in the men's cycling team pursuit after beating France in their heat.
But Steve Cummings, Paul Manning, Chris Newton and Bradley Wiggins face a struggle for gold after Australia smashed the world record in their heat.
Also in the velodrome, Ross Edgar moved into the last eight of the sprint after ousting much-fancied Australian Sean Eadie in the repechage.
Victoria Pendleton failed to qualify from her repechage, finishing behind Germany's Katrin Meinke and Yvonne Hijgenaar from Holland.
Sarah Ulmer picked up gold for New Zealand in the final of the women's 3000m individual pursuit after clocking a world-record time.
But the Games were rocked by the news that shot put champion Irina Korzhanenko has failed a drugs test.
The Russian, who won the title with a throw of 21.06m, will be stripped of her gold.
And the Greek team endured more embarrassment with weightlifter Leonidas Sampanis also failing a dope test.
Earlier Team GB took their overall haul of medals to 20 following a silver in the women's quadruple sculls, made up of Rebecca Romero, Frances Houghton, Debbie Flood and Alison Mowbray, on the final day of the rowing regatta. Staying on the water, Paul Goodison failed to add a fourth medal to Team GB's haul on the Saronic Gulf after finishing fourth in sailing's Laser class. Brazil's Robert Scheidt took gold.
There was better news for Chris Draper and Simon Hiscocks, who moved into third overall after race 11 in the 49er class.
The rowing regatta finished with an American victory in the men's eight - their first gold in the sport's blue riband event since 1964.
Romania took the women's eight, a result that gave crew member Elisabeta Lipa a fifth Olympic gold. It also moved Romania to the top of rowing's medal table.
The opening round of the individual showjumping ended with a 10-way tie for the top spot after a host of riders enjoyed clear rounds. Britain's top rider Nick Skelton held a share of 11th.
The tennis tournament concluded as Nicolas Massu won his second gold of the Games. Following on from his triumph in the men's doubles, he ousted American Mardy Fish 6-3 3-6 2-6 6-3 6-4.
MMIX
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