Peirsol, US team smash world records

American Aaron Peirsol set a world record in the 200 metres backstroke and the US team did likewise in the 4x100 freestyle relay at the Pan Pacific Championships in Canada on Saturday.

Peirsol reaffirmed his place as an unbeatable force in the 200 metres backstroke with a time of 1:54.44, breaking his own world record by more than two-tenths of a second.

Peirsol holds nine of the fastest times posted in the event and has not lost an international competition in more than six years.

"With the backstroke you can really hear the crowd, and the crowd was great," he told reporters.

Led by multiple Olympic gold medallist Michael Phelps, the US 4x100 metres freestyle team also set a world record en route to a gold medal.

Phelps, Cullen Jones and veterans Neil Walker and Jason Lezak turned in a blistering time of 3:12.46, more than six-tenths of a second better than the previous mark set by South Africa at the 2004 Olympics.

Among the other highlights was South Korean teenager Tae Hwan Park's win in the men's 400 freestyle, his country's first gold medal at a major international meet.

Park, who turns 17 in September, outlasted American favourite Klete Keller to a time of 3:45.72.

Japan's Reiko Nakamura took gold in the women's 200-metre backstroke with a meet record of 2:08.86.