A pair of West Australians caused a stir in the pool, while the nation has a new world record holder after an eventful day of action at the Australian Swimming Championships.

Brianna Throssell sent a message to her rivals as she swept the field on her way to the 100m butterfly title, while Zac Incerti made a statement in the 200m freestyle final.

However, Zac Stubblety-Cook was the talk of the town as he set a new world record in the 200m breaststroke, as the Tokyo gold medallist edged past the previous record to post a time of 2:05.95.

The Queenslander produced a dominant swim and finished more than four seconds clear of the rest of the field, celebrating with more than an air of disbelief in the aftermath.

Earlier, Throssell booked her spot in the Commonwealth Games squad, winning her butterfly final in a time of 57.31 - more than a second ahead of her nearest rival Alexandria Perkins.

The West Australian’s victory never looked in doubt, and after claiming three relay medals (including one gold) in Tokyo, Throssell will be hoping to outdo the bronze medal she won in the 100m butterfly at the previous Commonwealth Games.

Throssell was not the only West Australian to turn heads, as Zac Incerti overcame Elijah Winnington and Mack Horton to claim the 200m freestyle national title.

Incerti led at each turn and held off a strong finish from Winnington to post a time of 1:45.80, ensuring he would join Throssell on the plane to Birmingham.

Another West Australian, Holly Barratt, finished fifth in the 50m backstroke final.

Meanwhile, freestyle king Kyle Chalmers has floated the possibility of nominating for the World Championships in the butterfly - a decision which could have implications for pop star Cody Simpson’s swimming dreams.

Chalmers, who is taking a break from freestyle, finished second in the 100m butterfly final before winning the 50m butterfly final.

After originally saying he would not contest the butterfly at the World Championships, Chalmers said he was now considering a U-turn, which could result in Simpson missing out on selection despite a strong swim in the 100m butterfly final.