London: Usain Bolt answers the nagging question of whether he is still the fastest man on Earth on Sunday in an Olympic cauldron that almost boiled over when Britain's athletes enjoyed their greatest night on Saturday. The Jamaican won a golden treble with three astonishing world records at the last Olympics in Beijing. But since then he has lost his world title and his aura of invincibility.
Fans hoping the men's 100 metres final (2055 GMT) on the fast London track will top Beijing's may not have been reassured by the sight of Bolt stumbling in his heat but he was only in first gear and should glide through Sunday's semi-final.
The semis and the final later are also expected to include the three fastest men in history after Bolt - Jamaica's world champion Yohan Blake, compatriot Asafa Powell and Tyson Gay of the United States.
Asked by reporters on Saturday if he was in good enough shape to win gold, Bolt looked down at his feet and replied: "We'll see."
He can at least take inspiration from a crowd who cheered his first appearance to the hilt and from compatriot Shelly-Ann Fraser-Pryce, who on Saturday became only the third woman to win back-to-back Olympic 100 titles.
Women will also mak e sporting history in the boxing ring on Sunday when they compete on an Olympic stage for the first time, ending the last all-male sport at the Summer Games.
But if Sunday rewrites the record books, Saturday belonged to hosts Britain, who took three athletics golds and three more elsewhere to register their best day at an Olympics since the first London Games in 1908.
"Their extraordinary efforts have brought rapture to streets, parks and living rooms in London and all over the country if not the planet," Ma yor of London Boris Jo hnson said, s umming up a euphoric mood after Britain's gold rush.
Jessica Ennis, poster girl of these Olympics, collapsed in tears of relief after a capacity 80,000 crowd roared her to victory in the heptathlon.
She confirmed on Sunday that she would not run in the individual 100 hurdles l ater this week a s she looks forward to some rest - as well as va st Br itish media attention a nd a sl ew of sponsorship opportunities that will inevitably follow.
Greg Rutherford was also hailed a hero by British newspapers after winning a surprise long jump gold while Mo Farah, born in Somalia but brought up in England, took Britain's first 10,000 gold to break 16 years of Ethiopian domination in the event.
Kenenisa Bekele, winner at the last two Olympics, finished fourth.
"I just can't believe it, the crowd got behind me so much. I've never experienced anything like this. The best moment of my life," Farah said.
British medal success and the exuberance of fans across the venues have begun to create an Olympic buzz across Britain.
On Saturday former Beatle Paul McCartney got in on the act by leading the crowd in singing the "Hey Jude" hit to serenade the women's team pursuit cyclists who made it four golds for Britain in five track cycling events.
The customary "Dorney Roar" also pushed two British rowing crews to gold and one to silver on Lake Dorney outside London.
The home gold run could continue when Ben Ainslie takes to the waters off Weymouth o n England's south coast on Sunday with his faithful Finn dinghy "Rita", aiming to become the most successful Olympic sailor ever.
Ian Percy and Andrew "Bart" Simpson sail immediately before Ainslie in their two-man Star keelboat, hoping to defend the Olympic gold they won in the class in China in 2008.
Andy Murray also shoulders Britain's dreams at Wimbledon, aiming to avenge his defeat by Swiss world number one Roger Federer in last month's gr a nd sl a m final. Murray is also due to team up with Laura Robson for the mixed doubles final.
Serena Williams goes for the doubles crown for America with sister Venus after her 6 -1 6-0 rout of Maria Sharapova in the w omen's singles f inal on Saturday se aled a "g o lden career slam" o f all four major tennis titles plus Olympic singles gold.
But she has a way to go to emulate the most decorated Olympian of all, her countryman Michael Phelps, who was given a rapturous send-off in the pool on Saturday at the end of his competitive career.
Phelps swam his favourite butterfly stroke in his farewell race to help the United States to victory in the 4x100 medley relay, an event they have never lost.
The medal was his 18th gold in an Olympic career stretching back to Sydney in 2000 and his 22nd of any colour, four more than the previous record held by Soviet gymnast Larisa Latynina.
"I've been able to do everything I wanted," he said. "I've been able to put my mind to the goals that I wanted to achieve and (coach) Bob (Bowman) and I have somehow managed to do every single thing."
The first medals of day nine will be won in the women's marathon, being run in the pouring rain on a course around many of London's big tourist attractions.
United States finished day eight at the top of the medals table with 26 golds followed by China on 25 and Britain on 14.
The Americans cemented their dominance in the pool by winning the women's medley relay in world record time but had to share the last-night swimming limelight with China's Sun Yang.
Sun slashed more than three seconds off his own world record to win the men's 1,500 freestyle to go with his 400 gold.
Dutchwoman Ranomi Kromowidjojo won the 50 freestyle. Having already claimed the 100, she is unchallenged as the fastest woman in the pool.
In London's Hyde Park, the women's triathlon came down to a photo-finish, the first in the sport.
After just shy of two hours of swimming, cycling and running, Switzerland's Nicola Spirig was judged to have beaten Lisa Norden of Sweden by just 15 centimetres in a ferocious sprint finish that Sunday's 100 metres cast will do well to match.
London: Usain Bolt answers the nagging question of whether he is still the fastest man on Earth on Sunday in an Olympic cauldron that almost boiled over when Britain's athletes enjoyed their greatest night on Saturday.
The Jamaican won a golden treble with three astonishing world records at the last Olympics in Beijing. But since then he has lost his world title and his aura of invincibility.