Australia's O'Callaghan sets sights on Titmus's 200m freestyle world record
O'Callaghan owns two of the three fastest times in history with only retired fellow Australian Titmus going quicker when she swam 1:52.23 at the Olympic trials in 2024.
That was good enough to better O'Callaghan's previous world record, and she wants it back.
"I don't like to put pressure on myself, but definitely I would love to go a 1:51," she said after beating Lani Pallister (1:55.66) and New Zealand's Erika Fairweather (1:55.72) on the Gold Coast.
"I think that's in my sights right now, and that's giving me the drive. The girls are always pushing me domestically and internationally."
An equally untouchable Kaylee McKeown won her third race of the meet when she surged home in the 200m medley in 2:09.22 ahead of Ella Ramsey (2:09.94).
It is a discipline she has not raced for a year but McKeown said it would be on her agenda through to the 2028 Olympics, setting up a showdown with Canadian superstar Summer McIntosh.
"I took a year off doing medley work, so slowly getting back into it. I'm happy with where I'm at," she said.
"I would love to," she added of swimming the event at the Olympics. "I think a lot of people tend to think I just do backstroke, so it's nice to kind of surprise myself and them."
Olympic champion McKeown also won the 100m and 200m backstroke at the three-day meet as she steps up her preparations for the Commonwealth Games and Pan Pacific Championships this year.
Pallister, who collected the 400-800m freestyle double, added the 1500m when she hit the wall in 15:44.07, with Sam Short also achieving the three-peat, winning the men's 1500m in 14:54.75.
With world-record holder Cameron McEvoy not swimming, Jamie Jack took out the men's 50m freestyle in 21.71 while New Zealand's Lewis Clareburt won the 400m medley by a fingertip in 4:10.10.
In other races, former world champion Sam Williamson (27.14) came first in the men's 50m breaststroke and Matt Temple (51.60) powered home in the 100m butterfly.
Elizabeth Dekkers clocked an impressive 2:05.39 in the 200m butterfly, behind only McIntosh and American Regan Smith this year.
Alexandria Perkins (27.79) took out the women's 50m backstroke in the absence of world record holder McKeown who focused on the medley.