Jamaican Asafa Powell set a new men's 100m record of 9.77 seconds at the Athens Olympic Stadium on Tuesday.
Powell had predicted earlier this week that he would beat Tim Montgomery's previous best of 9.78, which the American set in Paris three years ago.
The 22-year-old stunned a quality field but had to wait several minutes for the time and wind level to be checked before the record was confirmed.
He said: "It shows no-one knows how fast a man can run."
Powell had spoken confidently about surpassing Montgomery's mark after he clocked 9.84 - the joint-third fastest time in history - in Kingston last month.
And in calm conditions in Greece, Powell's promise paid off as he streaked home well ahead of Ghana's Abdul Zakari and compatriot Michael Frater.
100m SINCE 1990
9.90: L Burell (US), 14/06/91
9.86: C Lewis (US), 25/08/91
9.85: L Burrell (US), 06/07/94
9.84: D Bailey (Can), 27/07/96
9.79: M Greene (US), 16/06/99
9.78: T Montgomery (US), 14/09/02
9.77: A Powell (Jam), 14/06/05
But Powell, who ran nine legal sub-10 second races last season, said the record did not make up for his failure to win gold at last year's Olympics.
He had been the favourite going into the race but trailed home in fifth behind winner Justin Gatlin.
"Nothing makes up for the Olympics, but this was showing the world I could have done it ," said Powell.
"I never knew it would really happen. I did have it on my mind but came here to do my best and it was a world record."
"It's really surprising to see I ran this time at this stage of the season."
Britain's Jason Gardener finished a disappointing ninth in 10.29 while Mark Lewis-Francis did not qualify for the final.
American Jim Hines became the first man to dip below the 10-second mark in 1968.
Since then the world mark has been lowered nine times - twice by nine-time Olympic gold medallist American Carl Lewis.
Maurice Greene, who held the record before Montgomery, also captured the record at Athens' Olympic Stadium in 1999.
"I am just happy to have set the record on a track where Maurice Greene also broke the world record," beamed Powell.
Powell has made great strides in only his third full season on the circuit but has fallen short of fulfilling his potential.
The Jamaican was disqualified at the quarter-final stage of the World 100m in 2003 for false starting, having set the fastest time in the first round of heats.
He then tied up in the Olympic final in Athens last August - but has made amends by blazing a trail in 2005.
As well as currently being ranked as the IAAF's number one male athlete in the world, he owns the top three fastest times over 100m this season.
Powell will now go to August's World Championships in Helsinki as overwhelming favourite.
The small crowd of a few thousand in the vast stadium almost saw a second world record but Qatar's Saif Shaheen, formerly known as Stephen Cherono when he ran for his native Kenya, narrowly missed out in the 3000m steeplechase.
Shaheen clocked the season's best time of 7 minutes 57.28 seconds, less than four seconds off his own record.