American teenager Missy Franklin became the first woman to win six golds at a single World Championships when she helped the United States to victory in the 4x100 metres medley relay yesterday.

The 18-year-old swam the opening, backstroke leg in Barcelona and the US triumph followed her titles last week in 100 and 200 backstroke, 200 freestyle and the 4x100 and 4x200 freestyle relays.

She was fourth in Friday’s 100 freestyle.

“It hurts really, really bad but now we’re all done and we’re all super excited,” a still-dripping Franklin, who is due to sign on at University of California, Berkeley later this year, told reporters.

“I think I’m going to take my time off until I get to Berkeley so I think that gives me about two and a half weeks. We’re all pretty excited about it.”

Franklin’s sixth gold is one more than the previous record of five she jointly held with compatriot Tracy Caulkins and Australia’s Libby Trickett.

The only other woman to win six golds at a major swimming meet was East German Kristin Otto at the 1988 Olympics in Seoul.

After her three world titles at the 2011 championships in Shanghai, Franklin is also tied for the most golds overall with Trickett on nine.

It was not a US double on the final day of competition, however, as France were handed a shock victory in the men’s 4x100 metres medley relay when favourites United States were disqualified.

The Americans touched first in three minutes 30.06 seconds before the stadium announcer drew gasps from the crowd and prompted wild celebrations among the French when he announced the US had been disqualified “for an early exchange”.

Official results showed 19-year-old Kevin Cordes, swimming the second, breaststroke leg, had jumped early by 0.04 seconds.

“A relay disqualification is not a particular individual’s fault,” US team member Nathan Adrian told reporters.

“It’s Team USA’s fault and it falls on all of our shoulders,” he added.

“It will really motivate Kevin. In the next couple of years we’re going to have the fastest breaststroker in the world.”

France clocked 3:31.51 to take gold, with Australia second in 3:31.64 and Japan third in 3:32.26.

The Americans were denied what would have been a 12th triumph in the event in 15 championships since the inaugural edition in Belgrade in 1973.

The drama echoed an incident at the worlds in Melbourne in 2007.

Michael Phelps’s bid to win eight golds was ruined when the US team was disqualified from the heats of the medley relay.

Meanwhile, China’s Sun Yang won a second consecutive world championships gold in the men’s 1,500 metres freestyle to complete a rare treble of distance titles.

The Olympic champion and world record holder clocked a time of 14 minutes 41.15 seconds, matching American teenager Katie Ledecky in winning 400, 800 and 1,500 freestyle titles in the Catalan capital.

Katinka Hosszu, of Hungary, won gold in the women’s 400 metres individual medley and the 50m freestyle title went to Ranomi Kromowidjojo.

Dutch girl Kromowidjojo clocked a time of 24.05 seconds.

Cate Campbell, of Australia, took silver in 24.14 and Briton Francesca Halsall claimed the bronze in 24.30, her nation’s first medal of the championships.

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