Amanda Beard broke the Olympic record to edge out great rival Leisel Jones and clinch the gold medal in the women's 200m breaststroke.
Australian Jones led from the start as she tried to erase the disappointment of missing out on gold in the 100m where she had been the hot favourite.
But she tired in the final few yards allowing American Beard, the world record holder in the event, to snatch victory in two minutes, 23.37 seconds.
Germany's Anne Poleska won the bronze.
Defending Olympic champion Agnes Kovacs of Hungary was fifth.
"It feels absolutely amazing," said Beard on winning the Olympic title.
She had previously won gold as a 14-year-old when she was part of the USA's victorious 4x100 medley relay team in Atlanta in 1996.
"I'm very proud,
very excited, very honoured. I can't wipe the smile off my