Kaylee McKeown has cruised through her return to medley swimming at the Australian championships in Adelaide.
McKeown has added the 4x100-metre medley to her program and was fastest in Thursday morning's heats.
She won two individual backstroke gold medals at last year's Olympic Games and also swam the backstroke leg in Australia's triumphant 4x100m medley team at the Tokyo Games.
The Queenslander was national 4x100m medley champion in 2019 but dropped the event from her Olympic schedule.
In her Thursday morning heat, McKeown swam well within herself in clocking four minutes 42.40 seconds, almost 10 seconds outside her personal best.
But she was still the quickest into Thursday night's final ahead of Jenna Forrester (4:43.02).
McKeown's swim came after Kyle Chalmers topped times in the men's 50m butterfly heats.
Chalmers, an Olympic gold and silver medallist in the 100m freestyle, is only swimming butterfly at the nationals.
And after finishing second in the 100m 'fly final on Wednesday night, Chalmers clocked 23.42 seconds over the shorter distance on Thursday morning.
Cody Simpson, the pop star who has returned to the pool and already secured Commonwealth Games selection after placing third in the 100m 'fly final, also advanced to the 50m butterfly final - his time of 23.79 was the fifth-fastest in the heats.
Reigning Olympic 200m breaststroke champion Zac Stubblety-Cook was quickest into the final of his pet event.
In the men's 200m freestyle, Zac Incerti was the fastest qualifier ahead of emerging 16-year-old Flynn Southam while dual Olympian Brianna Throssell was quickest in the women's 100m butterfly heats.
Chelsea Hodges headed times in the women's 50m breaststroke heats and Mollie O'Callaghan, after winning the 100m freestlyle on Wednesday night, was fastest in the women's 50m backstroke heats.
