Michael Phelps claimed a record seventh gold medal at the FINA World Championships to stake his claim to swimming immortality.
The 21-year-old American thus eclipsed the record of Australian Ian Thorpe, who had held the previous best of six golds at one World Championships.
It matches the major games feat of American Mark Spitz, who took seven gold medals at the 1972 Olympic Games in Munich.
Phelps had earlier been eliminated from contention for another gold when his team in the 4x100m medley relay was disqualified after Ian Crocker jumped into the water before the changeover was complete.
But he quickly recovered from that setback to set the new landmark in the 400m medley and smashing another world record to boot.
The American came home in 4:06.22 - beating his 4:08.26 in Athens at the 2004 Olympics, with fellow American Ryan Lochte 3.52secs behind in second and Italy's Luca Marin a further 0.14secs back to win bronze.
Melanie Nocher was the only Irish competitior on the final day of action in Melbourne.
She ranked 24th in the 400m individual medley, with a time of 4:59.82.
Poland's Mateusz Sawrymowicz took the gold medal in the men's 1500m freestyle to end the long run of success in that event of Grant Hackett of Australia.
The teenager finished with something to spare from second-placed Russian Yuri Prilukov and third-placed Briton David Davies.
Earlier, American Jessica Hardy took gold in the women's 50m breaststroke in a time of 30.63secs to edge out Aussie Leisel Jones by 0.07secs and compatriot Tara Kirk in third (31.05secs).
Briton Kate Haywood failed to match her qualifying time of 31.72secs, finishing seventh in 31.82secs.
Libby Lenton of Australia was the champion in the 50m freestyle, finishing ahead of Therese Alshammar of Sweden and Marleen Veldhuis of the Netherlands.
American Katie Hoff set a new world record as she claimed victory in the 400m medley. Hoff's winning time of 4:32.89 saw her beat off opposition from second-placed Russian Yana Martynova and third-placed Stephanie Rice of Australia.
