Peirsol wins 100m backstroke gold

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Video - Record time seals gold for Peirsol

Aaron Peirsol successfully defended his men's 100m backstroke title to win another gold medal for the US.

Peirsol, 25, set a new world record of 52.54 seconds to retain his crown ahead of fellow countryman Matt Grevers.

Australia's Hayden Stoeckel, who posted an Olympic record in the event during Monday's heats, shared bronze with Russia's Arkady Vyatchanin.

Exeter's Liam Tancock led at halfway but faded fast to finish sixth in the second 50m as Peirsol stormed home.

"All eight guys were capable of some amazing things," Tancock told BBC Sport after the race.

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Tancock looking at positives

"I'm really pleased with that, I had to do what I could - I went out fast and couldn't bring it home. Bring on London," the Briton added.

Peirsol, who had lowered his own world record at the US trials in Omaha last month, said the exertion of winning his fourth Olympic gold medal had taken its toll.

"It doesn't get any easier, to be honest," said Peirsol, who launches his defence of the 200m backstroke title on Wednesday.

"The knowledge and experience that you have done it once and can probably do it again does help.

"That is what I tried to keep in mind, but I really wanted to race and the guys around me pushed me to what I did today.

"The best thing about it was having Matt right behind me, we wanted an American one-two finish."

Grevers, who also won a gold as a heat swimmer in the historic 4x100m freestyle relay on Monday, paid tribute to his team-mate.

"I have been fortunate enough to get some private lessons from Aaron and some of the things he does are just perfect," said the 23-year-old.

"I don't know if it is his shoulder strength or what, but the amount of water he is able to hold is incredible.

"He has got a great mind, he can perform when it matters."

"It's been an amazing experience to be here, a few months ago a few people thought I wouldn't even be on this team," he admitted.