Caeleb Dressel captured three gold medals inside 90 sensational minutes on Saturday, taking his personal haul at the world swimming championships to six with a seventh on the cards on Sunday.

Dressel capped his stunning display by helping the United States to a world record in the mixed 4x100m freestyle relay having kicked off his historic night by winning the men's 50m freestyle and 100m butterfly golds in the space of half an hour.

He completed the hat-trick by swimming the opening leg of the relay before Simone Manuel touched the wall at three minutes, 19.60 seconds to seal America's win.

It's thought to be the first time a USA swimmer has won three golds medals in one day at a world championships.

"I haven't had much time to think tonight," said the 20-year-old.

"It's back-to-back events, it's physically demanding and mentally it's even more straining."

The relay time shaved more than three seconds off the previous record the US team set two years ago in Kazan.

The Netherlands took silver at 2.21 secs back while Canada claimed bronze at 3.95.

The championships close on Sunday with the USA well ahead in the medal table with 14 golds, 10 silvers and seven bronzes in the swimming events.

Dressel has now won six golds in Budapest.

He has three individuals titles, including the 100m freestyle, plus victories for the USA in the men's 4x100m freestyle, mixed 4x100m medley and mixed 4x100m freestyle relays.

He could win a seventh gold in the men's 4x100m medley relay on Sunday.

"I have 24 hours to my next swim, so I'll give myself 30 minutes tonight to let it sink in a bit and then it's time to refocus for the next event tomorrow," said Dressel.

- Ledecky's 14th worlds gold -

His haul overshadows even compatriot and freestyle queen Katie Ledecky, who leaves Budapest with five golds and a silver.

The 20-year-old Ledecky won her 14th world gold, spanning three championships, with victory in the women's 800m freestyle on Saturday, but was happy for Dressel to take the limelight.

"He's incredible, he's just a great athlete," said Ledecky.

"The way he goes about his racing, it's really impressive. He's really fired up Team USA with his performances in the water this week."

Dressel's relay team-mates paid tribute to his jaw-dropping performances.

"It's unbelievable man," said Nathan Adrian, who swam America's second leg on Saturday.

"It's unheard of until now -- everything is impossible until someone does it."

Manuel, the world and joint Olympic 100m freestyle champion, said Dressel deserves his success.

"He's an amazing athlete and he knows how to race," said Manuel. "He is trained for it, it that's how we all have our successes.

"Sometimes it comes out as a surprise when you work hard and you get what you achieve, but you worked hard for it."

Mallory Comerford, who swam the third leg, said Dressel's performances in the individual finals had inspired the relay team.

"It's amazing to know that he's leading us all off," said Comerford.

"It's inspiring to watch him swim and do well, it brings conference to the relay."

In Dressel's shadow, Sweden's Sarah Sjostrom won the women's 50m butterfly to complete the sprint double after her 100m earlier in the week.

It made up for some of the disappointment of missing gold in the women's 100m freestyle final on Friday by 0.04.

Sjostrom also set a new world record in the semi-finals of the 50m freestyle with a time of 23.67sec bettering the old mark of 23.73sec set by Germany's Britta Steffen in 2009.

The 23-year-old now holds world records in the 50m freestyle, 100m freestyle, 50m butterfly and 100m butterfly.

There were tears of joy in the women's 200m backstroke final as Emily Seebohm of Australia broke down after retaining her title.

A powerful burst in the final 50m saw Seebohm beat local favourite Katinka Hosszu, who took silver.

source: AFP