RIO DE JANEIRO, Aug 13, (AFP) - Britain smashed their own world record to win Olympic gold in the women's team pursuit in Rio on Saturday.

It was the third time in the space of 48 hours that the quartet of Katie Archibald, Laura Trott, Elinor Barker and Joanna Rowsell-Shand had set a new world mark in the 4km race. They had already set world records in qualifying and their semi-final.

"In the semi-final we rode more within ourselves, the girls came off the track saying that was about 80 per cent," said Rowsell-Shand, who as part of the winning team four years ago alongside Trott and Danielle King, when the women rode 3km in a three-rider team.

"All we had to do in that ride (the semi-final) was beat Canada, which we did, so we thought we might go a bit quicker in the final, but we also thought we might run a bit closer with America.

"You always go quicker when you're chasing a team - I think we knew we had more in the tank."

The 2012 London Olympic champions beat world champions United States by more than two seconds in the final at the Olympic velodrome. USA had briefly taken the world record in their morning semi-final but Britain, who first broke it on Thursday, improved on that in both their semi-final and final.

The Americans got off to a faster start in the final and were up by half a second after the opening 250-metre lap. But the Brits went ahead definitely 1.5km into the race and from there they simply put the hammer down and pulled away to win in a time of 4min 10.236sec.

"We weren't expecting to go into the lead until perhaps the final kilometre, so when our coach was walking us up (showing them they were ahead of schedule) with six laps to go, that was quite a nice surprise," added Rowsell-Shand.

The US actually went almost as fast as their brief world record run of the morning but the Brits - who broke the record in each of their three runs during the Games - proved they had an extra gear.

For seven-time world champion Trott, it was a third Olympic crown having won gold in this event and the omnium in London four yeas ago.

Canada beat New Zealand to take the bronze medal. Britain's victory completed a team pursuit double after the men's team of Bradley Wiggins, Ed Clancy, Steven Burke and Owain Doull also won gold in a world record time on Friday.