Felix Sanchez of the Dominican Republic recaptured the Olympic 400 metres hurdles title on Monday at the age of 34, eight years after he first won it, but other great champions lost their crowns in an emotional night at the London Games.
Sanchez was convulsed with sobs and tears streamed down his face as he stood on the victor's podium after holding off Michael Tinsley of the United States.
"No one expected this. A lot of people said I should retire but I stuck with it. They'll all be celebrating now," said Sanchez, who was shattered when his grandmother Lillian died during the Beijing Olympics. After his victory, he took out a picture of her from his name label and kissed it.
America's Angelo Taylor, 33, was thwarted in his attempt to become the first man to win three titles in the event after gold in 2000 and 2008. He could only manage fifth.
On a tough night for defending Olympic champions, Valerie Adams of New Zealand was pushed into second place in the women's shot put by Nadzeya Ostapchuk of Belarus, the 2005 world champion.
And Yelena Isinbayeva of Russia, bidding for a third successive gold medal in the pole vault, could only manage bronze behind Jennifer Suhr of the United States and Yarisley Silva of Cuba.
Russian world champion Yuliya Zaripova won the women's 3 000 metres steeplechase, leading from the start on a chilly and rainy evening and storming across the line well clear of Tunisia's Habiba Ghribi and Ethiopia'sSofia Assefa.
Two 19-year-olds took gold and silver in the men's 400 metres, with Kirani James of Grenada powering through ahead of Luguelin Santos of the Dominican Republic.
It was Grenada's first-ever Olympic medal, while Javier Culson took bronze in the hurdles to give Puerto Ricoits first medal in athletics.
OVATION FOR BOLT
There were huge cheers and an explosion of flashbulbs around the 80 000-capacity Olympic Stadium whenUsain Bolt leapt onto the podium to receive his gold medal for winning Sunday night's 100 metres final.
That put him on course for a unique double-double in 100m and 200m races at successive Games and keptJamaica in the hunt for a second sweep of individual sprint medals after Shelly-Ann Fraser-Pryce retained her women's 100m crown.
Bolt also has his eye on more medals, saying after Sunday's victory: "I'm never going to say that I'm the greatest until I've run my 200 metres."
Some had doubted that Bolt had it in him to win a repeat gold in the 100m after suffering back problems, getting himself disqualified for a false start in last year's world championships and losing to Yohan Blake in the Jamaican trials.
Despite a cautious start, he blitzed his way down the track to win in 9.63 seconds, an Olympic record and the second fastest time ever behind his own world best of 9.58.
But Bolt appeared in no great rush to turn his attention to Tuesday's 200m qualifying round, as newspaper pictures showed him celebrating his 100m gold with friends at 3 a.m.
Hundreds of Bolt fans back in Jamaica had braved the wind and heavy rain of a gathering tropical storm to watch outdoor screenings of the 100m final, some stopping their cars in traffic to do so.
"I can't drive off now, man," one motorist told a policeman trying to get traffic to move. "Give me a ticket if you want, but I am going to watch that race on that big screen."
OUT, THEN IN
In a bizarre sequence of events, Algerian Taoufik Makhloufi, a medal prospect in the 1 500m, was provisionally thrown out of the Games for not trying hard enough in an 800m heat, but later reinstated.
He beat champion Asbel Kiprop of Kenya in Sunday's semifinal of the 1 500m and did not plan to run in the 800m heats, but the International Association of Athletics Federations (IAAF) said his team had failed to withdraw him in time and he had to compete.
When he stepped off the track after jogging round for half a lap, the athletics referee disqualified him from all further events for not making a bona fide effort.
His team said he had a knee injury. The IAAF later said in a statement his disqualification had been revoked after a review of medical evidence.
Italy's reigning Olympic 50km walk champion Alex Schwazer was another athlete excluded from the London Games after he failed a doping test, Italian state broadcaster RAI reported on Monday after speaking to his coach Michele Didoni.
And American judoka Nick Delpopolo was barred after testing positive for marijuana, which he blamed on unwittingly eating a "hash brownie".
Away from the athletics stadium, South Korea and Brazil celebrated their first ever gold medals in gymnastics.
Yang Hak-seon won the men's vault with his spectacular triple-twisting front somersault. Brazil's Arthur Zanetti flexed his bulging biceps to topple China's 2008 Olympic champion Chen Yibing and secure victory in the men's rings.
Aliya Mustafina upset the favourites in the women's asymmetric bars to collect Russia's first gymnastics gold of the Games.
Britain's Jason Kenny overcame France's Gregory Bauge to win the Olympic track cycling sprint gold, while the hosts also won team show jumping gold after a tie-breaking jump-off with the Netherlands, while Saudi Arabia captured a bronze.
Iran's Omid Noroozi won gold in the 60kg Greco-Roman wrestling category on Monday, brushing aside Georgian outsider Revaz Lashkhi to take a second wrestling gold for his country in as many days.
Iranian fans roared and waved their country's red, white and green flag in a packed wrestling arena after Noroozi won the bout without dropping a point.
Noroozi wrestled one of his coaching staff to the ground in a playful celebration before running around the mat waving the Iranian flag.
Waiter Giovanni Cernogoraz served up a gold for Croatia when he overcame tears and Italy's Massimo Fabbrizi in a shootoff to win the men's trap shooting event.