Ariarne Titmus has locked in her first Olympic showdown with American Katie Ledecky, qualifying third-fastest for the 400m freestyle final.
The Tasmanian swimming star comfortably won her heat on Sunday night, clocking 4:01.66 to secure lane three with Ledecky (4:00.65) in lane four and China's Li Bingjie (4:01.57) in lane five.
"It's a comfortable swim. It's just a hit-out," Ian Thorpe said on Channel Seven.
"I thought Ariarne might have gone a little bit faster, but that last 100 if she wanted to she could have taken off - she chose not to.
"We've already heard Ariarne - it's who breaks the world record that will win this race."
Titmus will contest the final at 12.20pm on Monday before turning her attention to the 200m freestyle heats around 8pm.