Olympic champion Ariarne Titmus of Australia set the world record in the women’s 400-meter freestyle, powering to the gold medal in 3 minutes, 55.38 seconds at the swimming world championships Sunday.

Titmus eclipsed the 3:56.08 set by Summer McIntosh earlier this year and finished 3.35 seconds ahead of silver medalist Katie Ledecky of the United States. New Zealand’s Erika Fairweather edged out McIntosh to grab the bronze, finishing 4.21 seconds behind Titmus.

“It wasn’t something [breaking the record] that I had my mind on for this meet,” Titmus said. “I just wanted to come here and try and swim the way I know I’m capable of. I knew the only way to win, I believed, was to try to take it out [fast], and whoever had as much fight left at the end was going to win it.”

It was Titmus who laid down a marker for next year’s Paris Games, taking the lead 100 meters into the race and never looking back.

The 22-year-old Titmus has not lost a 400 freestyle race she has competed in for five years.

“I’ve put in a lot of work the past six weeks that I’ve been really happy with and took a lot away from trials,” Titmus said. “I swam the way I wanted to but knew I had enough time to turn that around and came here tonight and tried to be fearless.

“Summer and Katie are both class acts, and there’s hardly any faults in their racing. I knew the only way was to try and take the win. … I guess [it was] whoever had the most fight in the end and whoever had the best left in the tank.”

The clash between the trio of Titmus, Ledecky and McIntosh had generated “race of the century” hype, 20 years after Ian Thorpe beat Pieter van den Hoogenband and Michael Phelps at the 2004 Athens Olympics.

Ledecky earned her 33rd gold or silver medal in the Olympics or worlds. She has missed out on a top-two finish only once at the two events, finishing fifth in the 200-meter freestyle.

She sounded content with her race and now looks to the 800 and 1,500, where she is almost unbeatable. She said the record seemed inevitable.

“I think you could see a world record coming,” Ledecky said. “Once a couple of people do something, more people start doing it. It’s been a very fast year of swimming, and it was predictable that it will be a really fast field.”

It was the first of three world records to fall on the opening day of the swimming events at the World Aquatics Championships. Leon Marchand broke the nearly 15-year-old 400 individual medley mark that had been held by Michael Phelps. Marchand won the race in 4:02.50, breaking Phelps’ record by more than a second.

In the 4×100 women’s freestyle relay, Australia set a world record of 3:27.96 in a dominating win. The United States took second in 3:31.93, while China rounded out the podium with 3:32.40 as all three nations automatically qualified for the Paris Games.

Reuters and The Associated Press contributed to this report.