Usain Bolt surged to the Olympic 200 metres title on Thursday at the head of a Jamaican medal sweep to become the first man to win the 100 and 200m sprints at successive Games.
The race capped a historic day when Kenya's David Rudisha broke his own 800m world record, leaving the field trailing from the gun, and Britain's Nicola Adams became the first woman to win an Olympic boxing title.
The sellout 80 000 attendance in the athletics stadium was matched at Wembley, where the biggest crowd for a women's Olympic soccer match saw the United States beat Japan 2-1 to claim their third straight Olympic gold.
Bolt's time equalled the fourth fastest ever run as he eased down in the last 30 metres, sensing that he was not on course to break his own world record. Silver went to his main rival and training partner Yohan Blake, and bronze to Warren Weir.
"I knew it wasn't going to be a world record when I came around the corner, I could feel it," Bolt said. "I really wanted to try to get a world record in the 200 metres but it was harder than I think."
Now unchallenged as the greatest sprinter of all time, Bolt could add a sixth gold medal if he can anchor Jamaica to a second successive Olympic 4x100m victory on Saturday, in the last athletics event.
Rudisha had his eye on history from the gun on a warm, still night, becoming the first man under one minute 41 seconds.
"I had no doubt about winning, but I was waiting for perfect conditions to break the record," he said.
London Games chief Sebastian Coe, himself a former 800m world record holder, added: "Instead of just doing enough to win the race, he wanted to do something extraordinary... Rudisha's run will go down in history as one of the greatest Olympic victories."
World record holder Ashton Eaton of the United States won the decathlon, comfortably ahead of compatriot Troy Hardee, and the Czech Barbora Spotakova claimed the women's javelin gold.
There was another American one-two in the triple jump, where world champion Christian Taylor produced this year's biggest leap to take gold ahead of Will Claye.
The United States' track and field successes put them back on top of the medals table with 39 golds ahead of China on 37.
Three golds for the host nation Britain on Thursday, including one for Adams and two more in taekwondo and individual equestrian dressage, kept them in third place.
With 25 golds, they have already gone six better than Beijing in 2008 and notched up their best performance since 1908, when London first hosted the Games.
Adams won her historic flyweight final comfortably on points, flooring China's triple world champion Ren Cancan in a four-round blizzard of punches.
Minutes later, Irish lightweight Katie Taylor followed her to gold, amid even louder roars, by narrowly beating Russian Sofya Ochigava.
But Britain's men's hockey hopes were dashed when the team were crushed 9-2 by the Netherlands in their semifinal. In the final, the Dutch will play the title holders Germany, who beat world champions Australia 4-2.
In the women's soccer final, two goals from midfielder Carli Lloyd ensured that the US women's soccer team took revenge for their defeat by Japan in last year's World Cup final.
Yuki Ogimi halved the deficit from close range after 63 minutes to launch a furious fightback, but Japan could not find an equaliser.
US President Barack Obama said he was incredibly proud of the American athletes in London and offered a "special shout-out" to the women's soccer team.
He might have been thinking of US runner Manteo Mitchell, who astonishingly secured a place in the final for his 4x400m relay team by running through the pain of a broken leg.
"As soon as I took the first step past the 200-metre mark, I felt it break. I heard it."
"As soon as I took the first step past the 200-metre mark, I felt it break. I heard it," he said. "I didn't want to let those three guys down, or the team down, so I just ran on it. It hurt so bad."
His teammates finished the job to record the fastest ever run in the first round of the Olympic relay.
The US also won their first women's water polo gold, beating Spain 8-5 in the final.
And Saturday's women's basketball final will be contested by France and the US, who have not lost at the Games in 20 years, after they beat Russia and Australia respectively.
Double-amputee Oscar Pistorius was denied the chance to run in the relay qualification when South African second-leg runner Ofentse Mogawane collided with Kenya's Vincent Mumo Kiilu and fell to the ground.
South Africa were given a place in the final on appeal, but Jamaica failed to qualify after Jermaine Gonzales pulled up injured.
Across Afghanistan, people put aside war worries to crowd around televisions and even into cafes normally closed for the fasting month of Ramadan to cheer on taekwondo fighter Rohullah Nikpai, their country's first and only Olympic medallist.
Nikpai won bronze in the men's featherweight category in 2008, and rewarded the home fans by repeating the feat in London.
Germans Julius Brink and Jonas Reckermann became the first European team to claim men's beach volleyball gold by beating Brazilians Emanuel Rego and Alison Cerutti in three sets.
Belgian track cyclist Gijs Van Hoecke was sent home from the Games after photographs appeared in British newspapers of him apparently drunk and being carried into a taxi after a night out in London.
In a doping case dating back to 2004, American time-trial cyclist Tyler Hamilton will officially be stripped of his Athens Olympic gold medal on Friday after he admitted to doping, a source at the International Olympic Committee (IOC) said.
Retired Russian Viatcheslav Ekimov will move up to gold.
Attention also began to turn to Sunday's Olympic closing ceremony, which will be titled "A Symphony of British Music" and feature a host of pop stars and some 4 000 local volunteers.
Music director David Arnold, who has devoted much of the last two years to the final act of the London 2012 Games, said he wanted it to be "the greatest after-party in the world".
George Michael, Ed Sheeran and Muse are among the acts who have leaked their participation ahead of time, and the music press is swirling with rumours that everyone from The Who to the Spice Girls, Madness or Adele could join them.