San Francisco Frontiers - O'Callaghan, Stubblety-Cook send world championship message at Australian trials

Olympic 200m champion O'Callaghan hit the wall at Adelaide in 52.87 ahead of Olivia Wunsch (53.38) with all eight finalists under the qualifying time for the event in Singapore next month.

Four of them were teenagers as the next generation steps up after the retirement of Emma McKeon and Cate Campbell, with coveted 4x100m relay spots at stake.

A dominant Australia were unbeaten in the relay at the worlds from 2019 until last year when their under-strength team was usurped in Doha by the Dutch.

They have won 4x100m relay gold at the last four Olympics, spearheaded by O'Callaghan, McKeon, Meg Harris and Shayna Jack in Paris last year.

Harris opted out of the Adelaide final after swimming the fastest heat on Friday but is expected to be on the team, but Jack only came eighth in the final to miss out.

"This is probably only my fourth 100m of the season, so definitely a tough one," said O'Callaghan on day five of the six-day meet.

"The depth just shows in this 100 how much pressure there is to perform and to get to the top.

"I'm pretty proud of these ladies, that they could show up, especially the younger ones, to step up and fill in the roles of the older girls who've retired."

O'Callaghan won three gold, along with a silver and a bronze in Paris.

But she was beaten into fourth over 100m by Swedish great Sarah Sjostrom, American Torri Huske and Hong Kong's Siobhan Haughey despite being the favourite.

Tokyo Olympic champion Stubblety-Cook made sure he is on the plane to face off again with Marchand, who edged him into silver at the last Games.

The last time he raced over 200m in Adelaide he stopped the clock in a world record 2:05.95 at the 2022 trials.

That mark has since been surpassed by China's Qin Haiyang, with Stubblety-Cook, who is on the way back from injury, content with 2:09.09.

"Pretty happy with that, to get the job done," said the Australian, and is now being coached by Mel Marshall, who long mentored British breaststroke great Adam Peaty.

"Probably wanted to go a little bit faster, but just building into the summer."

Ella Ramsay (2:23.92) led a one-two with fellow rising star Tara Kinder (2:24.61) in the women's 200m breaststroke, mirroring their feat in the 200m medley.

In other races, Joshua Edwards-Smith (1:56.94) and Bradley Woodward (1:57.14) were under the qualifying time in the men's 200m backstroke while Sam Short (14:52.43) won the 1,500m freestyle.

V.Mitchell--SFF