The London 2012 Olympic gold medallist came from behind to capture men’s 200 metres butterfly gold in brilliant fashion at the Melbourne Sports and Aquatic Centre.

Le Clos touched the wall in a time of 1min 48.27sec and struggled to hold back the tears as he collected his first world title since 2018, while Japan’s Daiya Seto notched 1:49.22 for silver and Switzerland’s Noe Ponti bagged bronze in 1:49.22.

"This is four years in the making," said the 30-year-old who is three gold medals away from matching American Ryan Lochte's record of 14 individual world short-course titles.

"The warrior spirit is back.

"It was always there but I had to find a way of channel it again.

"I know winning isn’t everything, but I have taken a lot of losses lately and been written off by people that are close to me.

"I moved to coaches that believed in me.

"It didn’t matter who was there tonight, I was prepared to die out there... and to remind these guys that I am still here."

Asked whether he was looking to better Lochte’s record, le Chos said: "That’s what I am here for.

"I need three more golds and I will be the best short-course swimmer in history."

It was a busy night of action in Melbourne with the United States winning five of the nine finals.

There were also two gold medals for home favourite Kyle Chalmers who triumphed in the men's freestyle final before anchoring Australia to the men's 4x50m freestyle relay crown.

All eyes were on the much-anticipated duel between Chalmers and Romania's David Popovici, the men's 100m freestyle world record-holders over the respective short and long courses.

But 17-year-old Popovici finished almost a second behind Rio 2016 Olympic gold medallist Chalmers who executed his race to perfection.

Jordan Crooks of the Cayman Islands got off a stunning start only for his wheels to come off as Chalmers came motoring back before finding an extra gear to power home in 45.16 to secure a championship record.

France's Maxime Grousset came second in 45.41, while the bronze medal went to Italy’s defending champion Alessandro Miressi who clocked 45.71.

Popovici set a world junior record with 45.64 but a world short-course title will have to wait another year.

Chalmers earned his second gold of the evening when he produced a sensational final leg in the men’s 4x50m freestyle relay final.

The Australian team which also featured Isaac Alan Cooper, Matthew Temple and Flynn Zareb Southam were in fifth position before Chalmers dived in.

Chalmers guided Australia to a time of 1:23.44 as Italy slipped to second in 1:23.48 and The Netherlands claimed bronze in 1:23.75.

Five-time Olympic gold medallist Emma McKeon delighted the home crowd when she secured victory by one hundredth of a second in the women's 100m freestyle.

Defending champion Siobhán Haughey of Hong Kong mounted a strong challenge, pushing McKeon until the very last stroke, but it was the Australian who touched first in 50.77 to set a championship record.

Haughey had to settle for second in 50.87, while Marrit Steenbergen of The Netherlands finishing third in 51.25.

The women’s 200m butterfly final saw a tussle between Americans Dakota Luther and Hali Flickinger that kick-started a superb day for the US team.

Flickinger held the upper hand over the first 100m before being overtaken by Luther who pulled off an impressive late surge to take the title in 2:03.37.

The silver medal went to Flickinger who clocked 2:03.78 while Australia’s Elizabeth Dekkers did brilliantly from lane one to take bronze in 2:03.94.

The success kept coming from the US as double Olympic champion Lilly King was crowned women's 100m breaststroke champion in 1:02.67.

Tes Schouten of The Netherlands sealed silver in 1:03.90, with Anna Elendt of Germany third in 1:04.05.

Nic Fink then made it three successive gold for the US when he overcame the challenge of Britain's three-time Olympic champion Adam Peaty to claim men’s 100m breaststroke gold.

Fink proved too strong, winning in 55.88 as Nicolò Martinenghi of Italy picked up silver in 56.07 and Peaty came away with bronze in 56.25.

The US’ fourth gold of the night came in the men’s 400m freestyle as Kieran Smith quickly established a lead and never looked back to win in 3:34.38.

Australia’s Thomas Niell produced a fine swim from lane two to bag silver in 3:35.05, while Lithuania’s Danas Rapšys earned bronze in 3:36.26.

The US made it five with victory in the women’s 4x50m freestyle after clocking a championship record of 1:33.89.

Torri Huske sent them on their way before Claire Curzan, Erika Brown and Kate Douglass kept the pace as the US held off Australia to take gold.

McKeon battled hard in the final leg but came up short against Douglass as Australia came second in 1:34.23.

The Netherlands were the bronze medallists after finishing in 1:35.36.