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Video - Australia's women win relay gold
Australia smashed the world record on their way to gold in women's 4x200m freestyle relay.
Their time of seven minutes 44.31 seconds was almost six seconds faster than the previous world best.
China and the United States fought a tremendous battle on the final leg but the Olympics host nation edged out their rivals to claim the silver.
It was the first time the Americans, who took bronze, had lost in the event since it began in 1996.
Australia's team comprised Stephanie Rice, Bronte Barratt, Kylie Palmer and Linda Mackenzie.
Their victory gave Rice her third gold medal of the Beijing Games following wins in the 200m and 400m individual medley finals, which were also achieved in world-record times.
The United States had set the previous world record of 7:50.09 for the 4x200m freestyle relay at last year's world championships in Melbourne.
"It's so exciting," said Rice. "This is my last Olympic event here so what a great note to finish on - world record and a first place.
"We went in knowing we had a really good chance and I wasn't nervous even though I have never led off a relay before. I was trying to enjoy the moment.
"I feel amazing, I finished such a great meet as part of the relay."