Meg Harris caught attention with a heat swim of 52.6 seconds on Wednesday morning – beating her personal best by more than three tenths of a second – but it was O’Callaghan, the two-time reigning world champion, who took victory in a time of 52.27.
O’Callaghan, who has a personal best of 52.08, edged out Harris (52.59) and reigning Olympic champion Emma McKeon (53.09).
Shayna Jack (53.2), Brianna Throssell (53.77) and Cate Campbell (53.91) rounded out the top six.
“I’m always wanting to improve and go past a PB,” O’Callaghan said. “I feel like no matter what race [it is], I’m not happy with it and want more. There is a part of me though that’s pretty happy to do that time.
“The depth is crazy. There is so much pressure because we have the best women in the world. The standard is better than an Olympic final.”
The women’s 100m freestyle is undoubtedly the most difficult individual event to qualify for on the Australian Olympic swimming team.
Mollie O’Callaghan won the women’s 100m freestyle. Credit: Getty
Only two spots are up for grabs in the 100m freestyle event when Australia’s trials run from June 10-15 in Brisbane. However, selectors usually take the top six from the race at trials to cover relay positions.
McKeon is the reigning Olympic champion, with a personal best of 51.96 from that race, but finished fifth behind O’Callaghan at last year’s world championships.
Meanwhile, three-time Olympian Bronte Campbell pulled out of the final due to a calf injury.
The 29-year-old, who took a break from swimming after the Tokyo Olympics in 2021, raced in the heats of the 100m freestyle on Wednesday morning. She clocked 54.13 and qualified eighth fastest for the final but was scratched before the evening session.
Elijah Winnington after victory in the men’s 400m freestyle.Credit: Getty
“Unfortunately, had to pull out of nationals with a little calf strain,” Campbell wrote on Instagram. “Back to getting some work done and the final stretch towards trials.”
Elsewhere, Elijah Winnington (3:41.41) managed a surprise win over Sam Short (3:41.64) in the men’s 400m freestyle.
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Short became a world champion for the first time last year but was pipped in the final metres in front of a moderate crowd at the Gold Coast Aquatic Centre.
It was Winnington’s fastest time in two years and a positive sign following a seventh place at last year’s world championships.
Paul Biedermann’s world record (3:40.07) and Ian Thorpe’s Australian record (3:40.08) appear in danger of falling sooner rather than later.
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