Olympic champion Kaylee McKeown edged Mollie O'Callaghan in a sizzling 100m backstroke victory at the Australian Open on Tuesday, while Lani Pallister dipped under the magical four-minute mark to take the 400m freestyle.
Backing up her dominant 200m backstroke win on Monday, McKeown hit the wall on the Gold Coast in 58.06, well clear of the reigning Olympic 200m freestyle gold medallist who touched in 58.98.
"I was really happy with my processes tonight," said McKeown.
"It's really nice being out there with Mollie and the other girls. It kind of takes the pressure off. You feel like you're racing with friends."
McKeown said last week a key goal this year was to reclaim her world record from American Regan Smith and be the first woman ever to go under 57 seconds.
Smith's world best is currently 57.13 and McKeown's 57.16.
The pair have an intense rivalry, sharing the 20 fastest times in history.
Pallister followed an impressive victory in the 800m freestyle with another speedy swim over 400m as she accelerates preparations for the Commonwealth Games and Pan Pacific Championships this year.
The 23-year-old touched in 3:59.36 to clock the fastest time of 2026.
"I'm happy with the 3:59. That's my second-fastest time ever, just behind worlds last year in Singapore," she said.
"So really happy with my progress this season and going forward into the Commonwealth Games and Pan Pacs – it's going to be a really big year."
Pallister is among a small cohort, including Katie Ledecky, Summer McIntosh and Ariarne Titmus, to dip under four minutes.
Shayna Jack claimed the women's 50m freestyle in 24.60 ahead of Olivia Wunsch and O'Callaghan, while Sam Short was untouchable in the men's 800m freestyle, coming home in 7:41.04.
In other races, Kyle Chalmers added to his 100m freestyle win by taking the 50m butterfly in a personal best 22.77 – the quickest of the year.
"Butterfly is something I've been putting a bit more time and emphasis on in training, so it's good to see that it's actually working," he said.
New Zealand's Lewis Clareburt (1:45.57) came first in the men's 200m freestyle while Alexandria Perkins (57.21) was always in charge of the women's 100m butterfly.
Four-time Olympic medallist Zac Stubblety-Cook was edged into third by Gideon Burnes (1:00.66) in the men's 100m breaststroke.