Hackett holds off Perkins' challenge

Grant Hackett punches the air after victory

Australia's Grant Hackett took the Olympic men's 1500m freestyle as he held off the challenge of compatriot Kieren Perkins.

Hackett seized the initiative early on and was never headed by Perkins. He quickly established a body-length lead and after the 1000m mark he extended his advantage.

Perkins, who went even quicker than in setting the quickest qualifying time on Friday, was unable to haul back Hackett's lead and found defending his Olympic title for a second time just too much.

Hackett's winning time of 14:48.33 saw him finish more than five seconds ahead of Perkins with Chris Thompson of the United States just pipping Alexei Filipets of Russia for the bronze.

This is everything. This is the one you really work for. It all comes down to this day. I've done it and I'm bloody happy," Hackett said.

Not to be outdone by their women's team the United States' men's 4x100m medley relay team also set a new world best. Lenny Krayzelburg, Ed Moses, Ian Crocker and Gary Hall raced to victory in 3mins 33.73secs.

Australia took the silver with Germany in the bronze medal position, while the British quartet of Neil Willey, Darren Mew, James Hickman and Sion Brinn finished eighth.