Australian swimmers have set another world record while harvesting three more gold medals to equal the nation's largest haul at a world championships.
Australia's world record in the mixed 4x100 metres freestyle relay followed Cameron McEvoy becoming the nation's oldest world champion and Kaylee McKeown completing a rare golden backstroke sweep.
McEvoy won the men's 50m freestyle on Saturday night in Japan and McKeown collected the 200m backstroke crown after earlier wins over 50m and 100m.
The mixed freestyle relay team of Jack Cartwright, Kyle Chalmers, Shayna Jack and Mollie O'Callaghan added an exclamation mark to capture Australia's 13th gold in Fukuoka, equalling the nation's record haul at the 2005 and 2001 editions.
The Dolphins will top the medal table at these worlds, which finish on Sunday night. They're eight golds clear of China, with seven finals to come.
The last time Australia topped the tally at the worlds was 2001, also in Fukuoka.
"It's always something that is probably in the back of our minds and it's something that gets spoken about quite a lot in the media, us leading the medal tally," Chalmers said,
"And it's something Australia was able to do in Fukuoka back in 2001 so to do that again and be a part of one of Australia's most successful teams is inspiring."
Australia have set five world record at this meet with O'Callaghan involved in four.
The 19-year-old created a 200m freestyle record and was involved in Australia's benchmark relays in the women's 4x100m freestyle and 4x200m freestyle.
Now, she's part of a mixed 4x100m freestyle relay team which saluted in three minutes 18.83 seconds, inside the nation's previous record of 3:19.38 at last year's worlds.
On Sunday night, O'Callaghan could equal Ian Thorpe's Australian record of six gold medals at a single world championships created in Fukuoka in 2001.
"I'm too busy to think about it, to be honest," O'Callaghan said.
Her latest achievement came as 29-year-old McEvoy, the oldest Australian to win a world championship, turned conventional swimming wisdom on its proverbial head.
McEvoy said his win proves elite swimming isn't just for young athletes and justifies funky training methods featuring rock climbing and callisthenics rather than endless laps of the pool.
"Hopefully, our different training methods feeds back into the swimming community," McEvoy said.
"And either gives older guys a little bit more longevity in the sport or allows others to hit their potential when they may not have necessarily hit it."
McEvoy clocked 21.06 seconds to triumph some 11 years after making his first Australian senior swim team, while compatriot Isaac Cooper (21.70) came fourth.
McKeown completed her golden sweep, winning the 200m title in 2:03.85 following her 50m and 100m triumphs.
"That means a lot, I didn't think I would be able to do that," she said.
In the women's 800m freestyle final, American legend Katie Ledecky (8:08.87) cruised to her sixth consecutive world title - a record for any event - with Ariarne Titmus (8.13.59) third and Lani Pallister (8:21.33) seventh.
Australia's Matt Temple (50.81) finished fourth in the men's 100m butterfly final.
In the women's 50m freestyle semi-finals, Jack was second-fastest into the medal race with a personal best 24.01 as Sweden's Sarah Sjoestroem set a world record of 23.61.
Emma McKeon (24.67) was seventh quickest into Sunday night's final while, in the men's 50m backstroke, Isaac Cooper (24.86) was ranked ninth to just miss the medal race.