Lani Pallister has written herself into the record books, becoming the first female swimmer to win three freestyle gold medals at a single world short course championships.
Her win in the women's 1,500 metres freestyle in Melbourne followed Isaac Cooper's silver medal in a controversial men's 50m backstroke final, which had to be re-run.
Pallister was untouchable on Friday night, lapping some of her rivals before finishing in 15 minutes and 21.43 seconds.
She was more than 25 seconds clear of the field, while setting an Australian record in the process.
The daughter of former Australian distance swimming great Janelle Elford, Pallister opened the world titles on Tuesday with victory in the 400m freestyle final and then backed up a day later to win gold in the 800m freestyle.
She was also part of the Australian women's 4x200m freestyle relay team that set a world record.
Pallister had a horror run with injury and illness over the past 18 months, undergoing heart surgery as well as battling an eating disorder and glandular fever.
She said she was thrilled with her results in Melbourne.
"I'm excited to go four from four. I couldn't have asked for much better, it's been an incredible experience," Pallister said.
Shattered Cooper left with silver
Cooper was denied a gold medal in bizarre circumstances.
He was first home in the final but less than half the field completed the race after an alarm sounded due to what meet officials described as a "technical error".
An hour later the final was re-run with Ryan Murphy of the United States touching ahead of Cooper.
Murphy's winning time was 22.64, slower than Cooper's initial time of 22.49, which would have been a world junior record and a personal best.
Cooper clocked 22.73 in his second effort to pick up the silver medal.
"I've been trying my best," Cooper said.
"I've gone through so many low points and all I want to do is to be able to stand on top and every time I do I get knocked back again."
Murphy said he felt Cooper deserved to claim the gold.
"I really feel for Isaac — he's 18 and going for your first individual world title and that's huge and an incredible accomplishment," he said.
"I'm going to talk to him and let him know that in my mind he won that race."
Cooper, who was banished from the Commonwealth Games team for misusing prescription medication, was bidding for his third medal after winning bronze in the men's 100m backstroke behind Murphy and gold in the 4x50m freestyle relay.
In the first race only three swimmers, including Cooper, continued with no rope falling at the 15-metre mark to stop the swimmers.
Officials conferred before deciding to reschedule the race with a full field of eight swimmers after they ruled there was no false start.
Australia also had to settle for silver in the mixed 4x50m freestyle relay with France bursting out of the blocks to smash the world record.
After Kyle Chalmers swam the opening leg, Emma McKeon anchored the Australian quartet and entered the pool out of a medal spot but powered home to finish second.
Mélanie Henique touched the wall for France in 1: 27.33, eclipsing the US-held record by 0.56, with Australia clocking 1:28.03.
Chalmers helped add another silver medal to the host nation's tally as a member of the Australian men's 4x200m freestyle team that finished second to the US, who won gold in a world record of 6:44.12.
Another world mark fell in the women's 50m backstroke with Canadian Maggie MacNeil breaking her own record by 0.02 with a time of 25.25.
American Claire Curzan (25.54) was second and Australian teen Mollie O'Callaghan (25.61) picked up bronze.
AAP/ABC
