The U.S. men's team has set a new world record in the 4 X 100 meters medley relay event at the Pan Pacific Swimming championships in Yokohama, Japan.
The quartet of Aaron Peirsol, Brendan Hansen, Michael Phelps and Jason Lezak finished the race in 3:33.48, 0.25 second faster than the old mark set by the American team at the 2000 Olympics in Sydney.
The record topped a very successful night for U.S. swimmers, with Americans taking four more gold medals.
Natalie Coughlin won her fourth gold medal of the championships by taking the women's 100 meters freestyle race in 53.99. Jodie Henry of Australia was second with American Jenny Thompson third.
Margaret Hoelzer of the United States won the women's 200 meters backstroke race in 2:11. Aya Terakawa of Japan was second and Canada's Jennifer Fratesi was third.
Also Thursday Ian Crocker of the United States won the men's 100 meters butterfly race in 52.45. Australian Geoff Heugill was second with Michael Mintenko of Canada third.
Michael Phelps of the United States won the men's 200 meters individual medley in 1:59.70. Japan's Takahiro Mori won the silver and the bronze went to American Thomas Wilkens.
Australia also earned two more gold medals on the night, with Grant Hackett taking the men's 1500 meters freestyle race in 14:41.65. Australia's women's team won the 4 X 100 meters medley relay in 4:00.5.
Thursday was the final day of the competition. The United States dominated the meet, winning 21 gold medals. Australia finished second with 11 golds.