Australian swimmer Kaylee McKeown set a new world record in the women's 100-meter backstroke with a time of 57.45 at the country's Olympic trials on Sunday.

The previous record of 57.57 was set by American Regan Smith in 2019.

McKeown, 19, said she was inspired by her father's death, which happened 10 months ago because of brain cancer, according to the Associated Press.

"With COVID and the passing of my dad in August last year, it has been a huge, huge buildup to these trials. And I have turned it into a bit of a hunger and motivation behind me," said McKeown. "I use it every day that I wake up. I know it's a privilege to be on this earth and walk and talk, so to get up and do that tonight is not really for me but my family."

After setting a new Commonwealth and Australian record last month with a time of 57.63, McKeown's coach Chris Mooney made breaking the world record her target.

"He did say something to me before I got in for warm-up. It was like, 'You know, buddy, I believe in you. I knew and he knew at that time, that it was go time. He knew something special was about to happen. I may not have known it, but I was just trying to keep the nerves down as much as I could," said the 19-year-old.

McKeown's incredible performance at the SA Aquatic and Leisure Centre has made her competition with Smith at the coming Tokyo Olympics more highly anticipated.

"It's just whoever comes up on the day. You never know what can happen in five, six weeks' time," said McKeown.