Australia's Kaylee McKeown set a new Olympic record as she won her second consecutive Olympic 100m backstroke title at the Paris Games on Tuesday.

McKeown finished in 57.33 seconds at La Defense Arena, beating her own previous mark of 57.47 set in Tokyo three years ago.

American world record holder Regan Smith took silver in 57.66 and her compatriot Katharine Berkoff claimed bronze in 57.98.

"It feels surreal to be honest with you, and I wasn't sure if I'd be any good there tonight," McKeown said after the race. "I didn't put expectations on myself, I was going to get out and enjoy the atmosphere, and that's the best you can do for yourself."

"I knew it was going to come down to the last five meters. She [Smith] pushed me the whole way through. You wait for the race and finish it, and I can't even remember it now."

The 23-year-old added: "The nerves were definitely there, but I reminded myself that it's a pool in a different venue, and I train every single day of my life. It was a great atmosphere. Without my glasses I can't see too much. I looked at the scoreboard and it soaked in for a hot second and then obviously you have a reaction."