World 400m freestyle champion Ariarne Titmus warmed up for the Olympics by claiming the Australian title Saturday in 4min 01.34sec as she eyes a Tokyo showdown with American great Katie Ledecky.
The 20-year-old, whose preparations were set back by a shoulder injury, turned at the halfway mark in an outdoor pool on the Gold Coast in 1:58.61 and powered home, although missed out on going under the magic four minute mark.
"Very happy with that ... especially knowing where I'm at in my work at the moment. I kind of forgot what a 400 felt like, but now I definitely remember," said Titmus, who won the 200m title on Thursday.
"I haven't seen the splits yet, but it was more about my attitude going into the race knowing I had to go for it. Hopefully, I'll look back at my splits and see that I did that."
Ledecky has also been in fine early-year form, winning the 400m at the Mission Viejo Pro Swim Series last weekend in 3:59.25.
Young prospect Elijah Winnington took out the men's title in 3:45.69 -- under Australia's Olympic qualifying standard ahead of the official trials in June. Defending Olympic champion Mack Horton withdrew to focus on his training regime.
"I went faster a couple of months ago, so still some stuff to work on definitely," said Winnington.
Veteran Emily Seebohm was also well under the qualifying standard in winning the women's 200m backstroke in 2:07.46 after Commonwealth record holder KayleeMcKeown opted not to race the final.
McKeown instead focused on the 200m medley, where she has the fastest time this year, comfortably claiming the title in 2:09.78.
Olympic silver medallist Mitch Larkin also sat out the men's 200m backstroke final after posting a sizzling 1:54.38 in the heats as he shapes up as a serious Tokyo medal prospect.
Like McKeown, he focused on the 200m medley and stormed home in 1:56.74. He now holds two of the world's three fastest times over the past 12 months.
Meanwhile, Emma McKeon won the Australian 100m butterfly title in 56.44, the second fastest time over the past year as she looks to better the sixth she finished at the 2016 Rio Games.