Titmus, McKeown challenge world records in Olympic statement swims

Olympic champion Ariarne Titmus fired a warning shot to rivals Katie Ledecky and Summer McIntosh Monday with the second fastest women's 400m freestyle in history, while backstroke star Kaylee McKeown narrowly missed the 200m medley world record.

The 23-year-old Titmus is unbeaten over the distance since 2019 and will head to Paris in red-hot form after hitting the wall in 3mins 55.44secs at the Australian Olympic trials in Brisbane.

She was under her own world record pace until the final 30 metres, missing out by just 0.06sec.

"I knew if I did my job tonight, I'd be going to Paris. Pressure's kind of off as well," said Titmus, who owns five of the seven quickest times ever.

"It was more of a chance for me to practice a race plan and see how I would go.

"Doesn't matter about what happens here, it's about what happens in six weeks' time."

Lani Pallister (4:02.27) also qualified for a showdown that is one of the Olympics' most anticipated, with Titmus set to be pitted against Ledecky and Canadian sensation McIntosh.

Titmus beat Ledecky in a thrilling final at the Tokyo Olympics, then broke the American's long-standing world record in 2022.

McIntosh bettered the mark last year before the Australian hit back to reclaim the world record months later.

The Canadian swam 3:59.06 in May to ensure she will be in France, with Ledecky looking to make a statement at the US trials later this month.

Titmus will also attempt to qualify for the 200m and 800m freestyle. She won gold over 200 and 400 in Tokyo and silver behind Ledecky in the 800.

All-conquering backstroke queen McKeown also set the pool alight, clocking the world's fastest 200m medley since the 2016 Rio Olympics and the fourth quickest ever.

She touched in 2:06.63 to miss Hungarian Katinka Hosszu's 2015 world record by a fraction, with fast-rising teenager Ella Ramsay (2:09.32) also punching her Paris ticket. 

 Best foot forward 

 "It's a bit of fun for me, I'm glad it's on the first night, kind of just get in the groove and get it out of the way," said McKeown, the defending 100m and 200m Olympic backstroke champion.

McKeown swam the fourth fastest 400m medley of all-time earlier this year, but has dropped the distance to focus on her other races.

Australia's most decorated Olympian Emma McKeon, who won seven medals in Tokyo, including four gold, won the 100m butterfly in 56.85 to join them at her third Games.

"I'm stoked," said 30-year-old McKeon, who claimed butterfly bronze in Japan.

"I chose to keep swimming after Tokyo because I felt like I had more to give, but also I wanted to see what I was capable of both physically and mentally."

But reigning Olympic 200m breaststroke champion Zac Stubblety-Cook missed out on qualifying for the 100m, with Sam Williamson (58.80) and Joshua Yong (59.48) instead making the grade.

Elijah Winnington, the 2022 world champion, touched first in the men's 400m freestyle in 3:43.26 ahead of last year's world champion Sam Short (3:43.90), with both heading to Paris with medal expectations.