The time compares 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.

Spitz said in a telephone interview from Detroit: "It goes to show you that not only is this guy the greatest swimmer of all time and the greatest Olympian of all time, he's maybe the greatest athlete of all time. He's the greatest racer who ever walked the planet."

Rebecca Adlington of Britain won the 800 freestyle, breaking Janet Evans' 19-year-old world record.

Usain Bolt of Jamaica celebrates winning the men's 100m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 16, 2008. Bolt won 100 metres gold at the Beijing Olympics in a world record time on Saturday, running 9.69 seconds to claim victory in an exhilarating showdown with his compatriot Asafa Powell. [Agencies]

Adlington finished in 8:14.10, bettering the oldest record in swimming of 8:16.22 and adding to her 400 freestyle gold.

Kirsty Coventry of Zimbabwe defended her Olympic title in the 200m backstroke, winning in a world-record time of 2:05.24 and lowering the mark of 2:06.09 set by Margaret Hoelzer at the US trials last month.

Cesar Cielo sprinted to gold in the men's 50 freestyle, defeating a field of heavyweight contenders with an Olympic record of 21.30 seconds.

The host nation's gold medal charge halted Saturday, with only one badminton gold won.

Zhang Ning, 33, successfully retained her Olympic crown after beating compatriot Xie Xingfang in a three-set thriller in the women's singles final.