Ariarne Titmus breaks 200m freestyle world record

Ariarne Titmus says breaking the 200m freestyle world record is a bonus from her unparalleled duel in the pool with compatriot Mollie O'Callaghan.

Titmus took the record from O'Callaghan in a stunning battle on Wednesday night at Australia's Olympic swimming selection trials in Brisbane.

The 23-year-old clocked one minute 52.23 seconds, bettering O'Callaghan's benchmark of 1:52.85 set at last year's world championships.

O'Callaghan also eclipsed her previous mark, finishing in 1:52.48 -- the second-fastest time in history.

Titmus, 23, now holds the 200m and 400m freestyle world records and is the reigning Olympic champion in both events.

"Honestly, the world record is a bonus," she said.

"I am happy to finally put together a swim that I know I'm capable of and it's exciting to do it in my home town, in front of a home-town crowd."

Titmus said she didn't use O'Callaghan's feat at last year's world titles in Japan as motivation, despite both swimmers being coached by Dean Boxall.

"We really don't see what each other is doing in training, we are very separate -- she trains for the sprint events, I train for middle distance," Titmus said.

"Looking at a world record, I don't look at who has it. I look at the time.

"Honestly, that wasn't really on my radar coming into this.

"I just wanted to put together a great swim and I have the chance to do it again in Paris."

The 20-year-old O'Callaghan admitted to some pre-race anxiety stemming from entering the final as the record holder.

"I couldn't really sleep last night," she said.

"I am still learning. I am only young and I am not as experienced as the other girls, so I will take anything at this point."

Such was the dominance of Titmus and O'Callaghan, they finished more than three seconds ahead of the rest of the field.

Lani Pallister finished third, Brianna Throssell was fourth and Shayna Jack tied for fifth with Jamie Perkins.

The top six swimmers will form Australia's 4x200m freestyle relay squad at the Paris Games starting on July 26 -- the nation holds the relay world record.

Jack's inclusion ensures she will make her Olympic debut in the French capital, having watched the 2021 Toyko Games from afar after completing a doping ban.

The now 25-year-old was initially suspended for four years after testing positive to the banned substance Ligandrol about three weeks before the 2019 world championships.

The Queenslander's ban was reduced to two years on appeal to the Court of Arbitration for Sport, which found she did not knowingly ingest the substance.

Jack's suspension ended in July 2021, two weeks before the Tokyo Olympics started but after the trials.