Michael Phelps equalled swimmer Mark Spitz's 1972 record of seven golds in one Olympics early today after coming from behind for a fingertip victory.
Trailing Serbia's Milorad Cavic on the final stroke in the 100 metres butterfly, he lunged towards the finish to touch the electronic pad an astonishing hundredth of a second ahead.
The Serbian team unsuccessfully appealed the result.
Indisputably the face of the Beijing 2008 Olympics, Phelps punched the air and screamed in joy as a capacity crowd in the Water Cube rose to hail him.
"It's pretty cool, that's all I can say," said Phelps, who thought halfway he had blown it. "I am in a sort of dream world."
Later on Saturday, the spotlight shifts to the Bird's Nest athletics venue, where the fastest men on earth face off in the 100m sprint in front of more than 90,000 people.
Russia's Valeriy Borchin made a triumphant entry to the stadium in the morning under a second day of sunshine and blue skies over Beijing to take gold in the 20km men's walk.
Borchin had a doping suspension as a junior, and three fellow Russian walkers were banned on the Games' eve for failing tests.
But it was hard to displace Phelps from the headlines.
The 23-year-old phenomenon now has 13 career golds, four more than anyone else in the 112-year history of the modern Games.
An unfamiliar seventh at the turn on Saturday, Phelps' second length was one of the comebacks of his career. He clocked 50.58 seconds to Cavic's 50.59, the finest margin possible in the pool.
It was close enough for Serbian officials to protest, but swimming's governing body FINA confirmed the result on appeal. "I personally looked at the video footage and it was very clear the Serbian swimmer touched second," race referee Ben Ekumbo said.
Phelps admitted he was hurting during the last 10 metres.
"It was my last individual race and I just wanted to finish as strong as I could," he said, laughing and waving at fans.
On Sunday, Phelps can go one better than Spitz in Munich with a chance for an eighth Beijing gold in the 100m medley relay.
Watched in every race by his mother and cheered to his first wins by President George W. Bush, Phelps' success is down to natural brilliance, total focus, and the perfect swimmer's physique of large torso and huge reach on relatively short legs.
His arm span is 3 inches (7.6 cm) more than his 6ft 4 height.
MUGABE'S "GOLDEN GIRL"
If successful on Sunday, Phelps can expect an avalanche of multi-million sponsorship details.
Already though, "he's a billion dollar man," Australian-based celebrity agent Max Markson said. "He won't have to get a job ever. He can live off this for 50 years."
Inevitably overshadowed by Phelps, women swimmers were nonetheless determined not to be outdone in the Water Cube.
Zimbabwe's Kirsty Coventry, who had won three silvers already in Beijing, finally struck gold in the women's 200 metres backstroke, bringing some rare cheer to her troubled homeland.
She shaved 0.85 seconds off the previous world best.
"I'm so excited I can hear my national anthem play, I'm so proud, it'll be exciting back home," said Coventry, who has been called a "golden girl" by President Robert Mugabe in a rare accolade from him for Zimbabwe's white minority.
Britain's Rebecca Adlington also smashed a 19-year-old world record to take gold in the women's 800 metres freestyle.
She had won Britain's first Olympic women's swimming title in nearly half a century in the 400 freestyle on Monday. "If anyone would have said before the Games that I'd win two golds and break the world record, I'd have laughed in their face," she said.
Then Brazilian Cesar Cielo Filho won the men's 50m freestyle to give his country their first Olympic swimming gold.
While the colour-changing Water Cube building has figured large in the first half of the Games, attention is now also firmly on the equally futuristic Bird's Nest stadium.
The blue riband track race, the men's 100m sprint, takes place in the evening in front of more than 90,000 people. It appears to be shaping into a fascinating three-man, two-nation affair.
Jamaica's Usain Bolt was in superb form in the heats on Friday, having time to look around and still win his second round race in the day's best time of 9.92 seconds.
Bolt has burst on to the 100m scene in the last year, shouldering aside American world champion Tyson Gay and fellow Jamaican former world record holder Asafa Powell to set a new best of 9.72 in May. He hopes to be the first man to complete the 100m and 200m Olympic double since American Carl Lewis in 1984.
Despite its tradition of producing world class sprinters, Jamaica has yet to win a men's 100m gold and the Caribbean islanders will be watching tensely at 10.30 pm (1430 GMT).
With a rise to sporting superpower status that mirrors their growing economic clout, China lead the gold medal table with 27 to the United States' 15. The hosts came second in Athens and would love to go one better in front of their 1.3 billion people.