Australia’s Ariarne Titmus (right) reacts after finishing first in the women’s 400m freestyle final during the Australian Swimming Trials at the Brisbane Aquatic Centre today. AFP PIC
Australia’s Ariarne Titmus (right) reacts after finishing first in the women’s 400m freestyle final during the Australian Swimming Trials at the Brisbane Aquatic Centre today. AFP PIC

MELBOURNE: Ariarne Titmus threatened her own 400 metres freestyle world record on the opening night of Australia's Olympic trials in Brisbane as she booked her ticket to the Paris Games with a blazing swim on Monday.

Though not fully tapered, the Olympic champion won the final in three minutes and 55.44 seconds, 0.06 seconds off her best from last year's world championships in Fukuoka – and the second fastest time in history.

It left Summer McIntosh's year-best mark of 3:59.06 far behind, while challenging American great Katie Ledecky, the woman Titmus beat for gold in a thriller at Tokyo, to produce an answer at the U.S. trials starting on Saturday.

Titmus said her coach Dean Boxall had sent her a text message in the afternoon saying she was "free like a bird."

"It was a bit of a free hit-out," said the Queenslander, also the 200m freestyle Olympic champion.

"I knew if I did my job tonight I would be going to Paris. Pressure's kind of off as well.

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

Minutes after Titmus fired up fans in the terraces, her brilliant Tokyo team mate Kaylee McKeown stormed to victory in the 200m individual medley final in a blistering personal best of 2:06.63.

Overhauling Canadian teenager McIntosh's career-best mark (2:06.89), the time was the fourth fastest ever and barely a half-second short of Katinka Hosszu's world record (2:06.12).

Only Hungarian Hosszu and the American Ariana Kukors have swum the event faster.

"It's a bit of fun for me," said McKeown, who owns the Olympic 100 and 200m backstroke titles.

"I'm glad it's in the first night – just get in the groove and get it out of the way. I'm really happy with that performance tonight."

Capping a thrilling first evening, Elijah Winnington claimed the men's 400 metres ahead of Sam Short in a duel of world champions.

They went stroke-for-stroke before Winnington pulled away in the last 100 metres to win in 3:43.26.

He and Short are in line to battle for podium places at Paris with Germany's Lukas Martens, who holds the year's best time of 3:40.33.

Emma McKeon, Australia's most decorated Olympic swimmer, booked her third Olympics by winning the 100m butterfly final in 56.85 seconds.

McKeon took bronze in the event in Tokyo, one of her women's record tally of seven swimming medals from a single Games.

Sam Williamson, world champion in the non-Olympic 50m breaststroke, punched his ticket to Paris with a personal best swim of 58.80 seconds in the 100m breaststroke final, while runner-up Joshua Yong also sneaked under the qualifying standard.

The trials continue on Tuesday, with world record holder McKeown set to race in the 100m backstroke.--Reuters