Lani Pallister became only the third woman to swim under 15mins 40secs in the 1500m freestyle Saturday, joining American great Katie Ledecky and Dane Lottie Friis.
Pallister hit the wall at the Australian world championship trials in Adelaide in 15:39.14, a new Commonwealth record.
"I was chasing No 2 all the time. I was looking at the rankings, and Lottie Friis is one that stood for a long time, obviously, only behind Katie," said Pallister.
"I fell apart with like 500 to go. I felt so sick. But I'm just really stoked with the week that I put together."
Friis' 15:38.88 was set in 2013. Ledecky owns all 23 fastest times ahead of that, including the world record of 15:20.48.
Pallister's time capped a breakthrough meet for the 23-year-old, who shattered Ariarne Titmus' 800m national record and went under four minutes for the first time in the 400m.
Ella Ramsay, 20, was another standout swimmer, booking a fourth event at next month's world championships in Singapore by winning the 400m medley in 4:36.12 ahead of Jenna Forrester (4:36.19).
She also won the 200m medley and 200m breaststroke and came second in the 100m breaststroke.
"Last day is always hard and even harder having the 400m medley," said Ramsay, with the trials in their sixth and final day.
"I had to keep it composed and I'm really happy with that time."
Ramsay was at the Paris Olympics and part of Australia's silver-medal winning 4x100m medley relay team. She came fifth in the 400m medley but a bout of Covid derailed her 200m medley campaign.
She joins Mollie O'Callaghan (50-100m backstroke and 100-200m freestyle) as the only swimmers to qualify for four individual events.
O'Callaghan missed out on making a fifth when she finished fourth in the 50m freestyle, won by Olympic silver medallist Meg Harris in 24.17.
Olivia Wunsch and Alex Perkins tied for second in 24.70, with a decision yet to be made on which one will take the second available slot.
Harris is a serious gold medal prospect with Swedish world record holder Sarah Sjostrom, who beat her to the Paris Olympic title, pregnant and not racing this year.
"That's what I was training for," Harris said.
"I found a new way to motivate myself this year, and I found a new appreciation for the sport."
Olympic 400m medley bronze medallist Brendon Smith punched his ticket with a 4:12.81 swim ahead of Will Petric (4:13.23), who also qualified.
A rejuvenated Kyle Chalmers will take on three events in Singapore after touching first in 22.89 in the 50m butterfly. Olympic 50m freestyle champion Cameron McEvoy was disqualified after coming second.