Australia's Stephanie Rice after winning the women's 400m individual medley gold August 10 2008. [Agencies]

Australia's Olympic debutant Stephanie Rice had an incredible day at the Water Cube Sunday. She not only beat favorite Katie Hoff of the US in the women's 400m individual medley to pocket her first Olympic gold. She also set an astonishing world record in the process.

Rice led all the way to the finish in 4 min 29.45 sec, shaving 1.67 seconds off the previous record set by Hoff in June.

Zimbabwean veteran Kirsty Conventry also broke the world record to win silver in 4:29.89.

Hoff seemed to have once again succumbed to nerves and was almost two and a half seconds behind Rice, settling for a bronze.

Fifteen-year-old American Elizabeth Beisel, who ranked first in Saturday's heats, finished fourth. China's 14-year-old Li Xuanxu, came in last.

Rice was excited with the record: "I was thinking it hurts a lot for (4 min and) 31 (sec). But when I saw it's (4 min and) 29 I thought it was amazing I thought no one could go under (4 min and) 30."

Racing against Hoff apparently pushed Rice faster. "It's the first time I've raced against Katie Hoff and Kirsty Coventry, but I tried not to think about any times and just swim my race.

"I knew I had to go out hard in the first 200 meters because butterfly and backstroke are my best strokes. I knew Hoff is an amazing breaststroker. So I got a lot of confidence turning at the end of the breaststroke knowing that I was in the lead."

Hoff tried to disguise her disappointment with a smile and said she was a little tired but happy to get her first ever Olympic medal. The 19-year-old from the same North Baltimore club that produced Michael Phelps earned a spot in five individual races and at least one relay.

Four years ago, Hoff made her Olympic debut as the youngest US swimmer, but she was so unnerved that she vomited on the pool deck and didn't make the 400m IM final.

Relay gold for Dutch

The Dutch quartet of Inge Dekker, Ranomi Kromowidjojo, Femke Heemskerk and Marleen Veldhuis won the 4x100m freestyle relay gold.

The foursome, who set the world record in March this year, clocked 3:33.76, almost one second off the Olympic record set by Australia in Athens.

USA ranked second and Australia, after a slow start, settled for the bronze.

"We went in the race as world record holders but knew the Australians and the US were really fast," said Veldhuis. "We just exploded in the water and the results were really good."

Xinhua