McKeon, Chalmers win 100m freestyle double

Australia has won the 100m freestyle double at the short course world championships with superstars Emma McKeon and Kyle Chalmers continuing the gold rush.

The host country has now won seven gold medals after the heavyweight duo stormed to victory in Melbourne on Thursday night.

Despite owning 17 Olympic medals between them, neither McKeon nor Chalmers had previously won an individual world championship race at either short or long course.

But McKeon couldn't be denied on Thursday night, blitzing the women's final to win gold with Siobhan Haughey from Hong Kong second and Dutch swimmer Marrit Steenbergen collecting the bronze medal.

Fellow Australian Madi Wilson was fourth.

With her former pop star boyfriend Cody Simpson watching from the stands, McKeon stopped the clock in 50.77 seconds, touching 0.10 ahead of defending champion Haughey.

"It was a tight finish - I only just realised after the race but to get my hand on the wall first is all you really want," McKeon said.

The reigning 50 and 100m Olympic champion, McKeon signalled her intentions with a blistering relay leg on Tuesday night which helped Australia win gold in the 4x100m freestyle relay in world record time - becoming the first woman to record a sub-50 second split.

McKeon withdrew from the equally successful 4x200m freestyle relay team to hunt her individual title.

World record-holder Chalmers motored home in the final lap of the men's 100m freestyle final to reel in race leader Jordan Crooks from the Cayman Islands, who faded from the medal positions.

Chalmers touched the wall in 45.16 - outside his world best time of 44.84 - with Frenchman Maxime Grousset second in 45.41 and Italian Alessandro Miressi taking bronze in 45.57.

The long course world record holder, Romanian teen David Popovici, was fourth.

"I had to pull out of the last three world short course championships due to injury and health issues so for me to finally make it to one and stand on the top of the podium is something I'm going to remember for the rest of my rest of my life," 24-year-old Chalmers said.

Isaac Cooper, who won bronze in the 100m backstroke, shocked the 50m backstroke field and will go into the final as the fastest qualifier with a personal best time of 22.52.

The 18-year-old was banished from the Commonwealth Games team for misusing prescription medication but has bounced back in style.

"It was really tough today as the fatigue is really setting in and in the warm-up pool I felt horrible," the young Queenslander said.

"I've known I've had that speed for a while and I'm glad I could execute."