Titmus fired a warning shot to both on Friday with the fastest 400m freestyle of the year, just 98 days ahead of Paris' Opening Ceremony in the Seine river.

The Olympic gold medalist went under four minutes at the Australian championships on the Gold Coast, hitting the wall in 3min 59.13sec to remain unbeaten in the event since 2019. Titmus beat Ledecky in a thrilling final at the Tokyo Olympics, then broke the American great's long-standing world record in 2022, only for Canadian teenager McIntosh to better the mark last year.

The Australian hit back months later to reclaim the world record, and the expected clash of the three in Paris is shaping up to be a blockbuster. "It's a good sign," said Titmus, who will again be aiming for the 200-400-800 treble again in France. She won gold in the 200 and 400 in Tokyo, and silver behind Ledecky in the 800.

"I am trying to think about my expectations on myself and what I want to do in Paris. I know there's a lot of pressure on me and I'm just trying to make the most of it," added the 23-year-old, who has swum four of the six fastest times in history," she continued. Lani Pallister finished second with a personal best of 4:01.75, ahead of the Australian Olympic trials in June.

After breaking Australian records in the 200m and 400m individual medley, Kaylee McKeown was on fire again in the 50m backstroke, a non-Olympic event in which she holds the world record. 

The 22-year-old clocked 27.07 to finish ahead of Mollie O'Callaghan (27.16) in the fifth fastest time ever. "I'm having a bit of fun trying to switch gears at this meet, it's been good training," said McKeown, also the world record holder in the 100m and 200m backstroke. 

Matt Temple signalled his intentions for Paris with the fastest 100m butterfly of the year, hitting to the wall in 50.80. Former world champion Cameron McEvoy and sprint king Kyle Chalmers both went under 22 seconds in the 50m freestyle, with the former claiming the title in 21.93 as he seeks a fourth Olympics. 

Elijah Winnington continued his stellar form with victory in the men's 800m freestyle, finishing half a length ahead of Sam Short in 7:43.08 after setting a world-leading time in the 400m freestyle earlier in the day. In other races, William Petric won the 200m individual medley in 1:58.43 ahead of New Zealand's Lewis Clareburt, the world 400m medley champion.