Reigning champion Usain Bolt coasted into the 100m final with apparent ease Sunday as America's Justin Gatlin led the timings for an Olympics showdown featuring the four fastest men in history.
Jamaica's Bolt, whose three sprint titles in 2008 were all in world-record times, looked relaxed and playful at the start and he shut down well before the finish, glancing sideways and easing up for a time of 9.87sec.
His team-mate Yohan Blake, nicknamed "The Beast", also won his semi-final in 9.85sec ahead of Tyson Gay, but Gatlin's bullocking 9.82sec was the day's quickest ahead of the final later on Sunday.
Dutchman Churandy Martina, America's Ryan Bailey, Jamaica's former world record-holder Asafa Powell and Trinidadian Richard Thompson -- the only man outside 10 seconds -- were the other men into the final.
"I am 'The Beast', so I have to go back and stay focused for the final," Blake said.
With Bolt, Gay, Powell and Blake topping the all-time 100m list, and ex-drug cheat Gatlin's personal best at 9.80sec, Bolt's three-year-old world record of 9.58sec could be under threat at London's Olympic Stadium.
Earlier, a day after Britain clocked up six golds -- their best Olympic performance in more than a century -- Andy Murray kept the shocks rolling as he routed Roger Federer 6-2, 6-1, 6-4 at Wimbledon to win men's tennis gold.
Just four weeks after losing to the Swiss at the same venue, denying Britain a first men's grand slam singles win in 76 years, Murray was crying tears of joy as he climbed into the stands to celebrate with his girlfriend and mother.
"That's number one for me. The biggest win of my life," Murray said. "This week's been absolutely incredible. I've had a lot of fun.
"I've lost some tough matches in some tough finals and that's hurt me a lot. But this is the best way to come back from the Wimbledon final."
However, Murray missed out on winning two gold medals on the same day when he and partner Laura Robson narrowly lost the mixed doubles final 2-6, 6-3, 10/8 to Belarus's Max Mirnyi and Victoria Azarenka.
Women's singles champion Serena Williams claimed her second London Games title, partnered by her sister Venus, with a 6-4, 6-4 win against Czech pair Andrea Hlavackova and Lucie Hradecka.
Britain's Ben Ainslie claimed his place in history as he won his fourth consecutive sailing gold, in the Finn class, making him the sport's most successful Olympian. But he ruled out trying for a fifth title.
"You can never say never but I don't think I can sail one of these again, it's killing my body so I don't think you will see me in Rio," Ainslie said in Weymouth, on Britain's south coast.
Mid-way through day nine, China were back on top of the medals table with 30 golds to 27 for the United States. Britain were in third place with 16.
As tension built for the men's 100m, at the other end of the distance spectrum the women's marathon was won by Ethiopian Tiki Gelana in the opening athletics medal of the day.
After a gruelling battle through London's streets which swept past some of the British capital's most iconic landmarks, Gelana raced home on The Mall in an Olympic record time of 2hr 23min 7sec.
Kenya's Priscah Jeptoo won the silver with Russia's Tatyana Petrova Arkhipova taking bronze.
Elsewhere, women's boxing made its debut in Olympic competition with the opening bouts in the women's flyweight and lightweight categories.
The first ever bout saw Russia's Elena Savelyeva defeat North Korea's Kim Hye-Song on points.
Denmark's Lasse Norman Hansen shook off a crash in the fifth and penultimate event to win gold in track cycling's omnium, halting a run of British titles at the Velodrome.
China completed the first clean-sweep of all five badminton gold medals, with Lin Dan winning a thrilling men's singles final against Malaysian rival Lee Chong Wei, and Cai Yun and Fu Haifeng triumphing in the men's doubles.
And the ex-hosts took a step towards a flawless, and unprecedented, haul of all eight diving titles when Wu Minxia won the women's 3m springboard -- equalling her ex-partner Guo Jinging as the sport's most decorated Olympian.
Chinese gymnast Zou Kai successfully defended his Olympic men's floor title, Romania's Sandra Izbasa won the women's vault and Hungary's Krisztian Berki was victorious in the men's pommel horse.
A total of 23 medals will be decided on Sunday, culminating in the men's 100m final at 9:50pm (0850 GMT).