The Tasmanian born swimmer clocked in at 3:59.35, which put her well under the world championship qualifying time of 4:06.48.

It's just 2.89 seconds away from the World Record time in long course set by American Katie Ledecky. However, the 18-year-old believes there’s still plenty of room for improvement.

“We were pretty fired up for this race and I have been swimming really quick and I wanted to try and put together a really great swim,” Titmus said.

“To be honest I am a bit disappointed with the time, I have been training really well and I thought I might have a 3:58 in me.

"I definitely felt the sting a little bit in the last 100 metres and I know I went out hard so that is probably why. With a bit more of a rest leading into a meet hopefully, that will help me.”

Also touching under the magic number was Kiah Melverton, with a time of 4:05.30.

Kaylee McKeown pulled out a personal best in the 200m Individual Medley and finished in 2:09.94 – placing first and under the qualifying time of 2:10.45.

Speaking after the race, an excited McKeown was very pleased with her result.

“So much effort has gone behind this swim and to come out with a personal best tonight is awesome,” she said.

“I was focussing on skills, not necessarily the speed and I think I have done that tonight.

“This obviously takes the pressure off for the rest of the week, so I am super stoked with that.

Griffith University’s Emma McKeon and UWA West Coast’s Brianna Throssell pushed each other all the way to the wall in the Women’s 100m Butterfly. Backing up impressive swims from this morning’s heat session, the duo both recorded times under the world championship qualifying time of 57.64.