Ian Thorpe won one of the most-anticipated swimming races in history when he pipped Pieter van den Hoogenband in the 200m freestyle.
The Australian beat the defending champion in a field which included the four fastest men in history.
He clocked an Olympic record of one minute 44.71 secs to edge the Dutchman with American Michael Phelps in third.
Thorpe's victory shattered Phelps' hopes of seven Olympic golds in Athens. Britain's Simon Burnett was seventh.
Van den Hoogenband took the early lead but was hunted down by Thorpe with just over 50m to go and had to settle for silver in 1:45.23.
Phelps was always trailing the leading pair and was consigned to bronze with a time of 1:45.32, a new American record.
"It was tough but I was able to produce a pretty good performance and I'm ecstatic about the result," said Thorpe, whose time was just 0.65 seconds outside
his own world record.
"I knew Pieter would go out quick and I just wanted to stay
The Dutchman sportingly embraced Thorpe after the race saying: "We've got one each now."
Thorpe won his first world title as a 15-year-old and was one of
the stars of the Sydney Olympics, winning three gold and two
silver medals as a 17-year-old.
American Klete Keller was fourth in 1:46.13 ahead of Australian distance star Grant Hackett (1:46.56).
Burnett was delighted to be competing among such vaunted company and recorded a time of 1:48.02.
"It was great coming out and with every name the cheer got louder and I knew it was going to be good," he said.
"Unfortunately I could not go faster - but my goal was not to come eighth and I did that. I wish I could have watched it on TV.
"I'd love to be in Thorpe's spot in four years time but I don't know about the pressure. I'm the only first time Olympian in the final so that's something in my favour."
In the men's 100m backstroke, Aaron Peirsol took gold in 54.06 with Markus Rogan of Austria second in 54.35. Tomomi Morita of Japan took the bronze in 54.36, while American world record holder Lenny Krazelburg was fourth.
Phelps returned later on Monday evening for the semi-finals of the 200m butterfly but was upset by Briton Stephen Parry, who won in a new Commonwealth record time of 1:55.57 from lane eight.
In the second semi-final, Pawel Korzeniowski of Poland won in 1:56.40 ahead of Japan's Takashi Yamamoto (1:56.69) and China's Wu Peng (1:56.81).