Summer McIntosh smashed the women's 400m freestyle world record in winning the title at the Canadian Swimming Trials in 3min 54.18sec on Saturday, sending a signal for this year's World Championships in Singapore.
McIntosh, a three-time Olympic gold medallist and former world record-holder in the event, sliced more than a second off the previous world record of 3:55.38 set by Australian Ariarne Titmus at the 2023 World Championships in Fukuoka, Japan.
"Going into tonight I knew that my training has been really good these past few months, and I knew that I could do something special," the 18-year-old star said. "I mean, I didn't think my training would be 54.1, but I'm really happy with that overall."
It was McIntosh's first race of the trials in Victoria, British Columbia, selection meet for the worlds in Singapore July 11-August 3.
She's entered in seven events, including the 800m free, 400m individual medley, 200m individual medley, 200m free, 200m butterfly and 200m backstroke.
She has indicated she aims to compete in five events at worlds.
McIntosh won gold in the 200m butterfly 200m medley and 400m medley at the Paris Games and she'll head to Singapore seeking to add to her tally of four world titles.
With Titmus taking a season off, she can expect her greatest challenge in the 400m free to come from Katie Ledecky, but after Saturday's showing McIntosh appeared more than up for a clash with the US great.
"To be honest I didn't really feel a lot of pain in that," she said. "I just felt so strong throughout and that's never been the case in the 400 freestyle for me.
"The last 100, I'm always really, really hurting, but I flipped up the 200 and I was just cruising, so I knew that I was having a strong swim.
"I could tell by the crowd and the way they were cheering that I was probably close to the world record, so I really tried to push that last part for them," McIntosh added.
LEDECKY CLOSES US SWIM CHAMPIONSHIPS
Nine-time Olympic gold medallist Katie Ledecky closed out the US Swimming Championships with her third title of the week, winning the 1 500m freestyle to book another event at this year's World Championships in Singapore.
Bobby Finke and Gretchen Walsh also grabbed their third wins of the week in Indianapolis, Indiana, to set themselves up for multiple medal campaigns in Singapore.
Ledecky clocked 15min 36.76sec to win the 1 500m free by more than 25 seconds. Claire Weinstein, who swam in a different heat of the timed finals was second-fastest in 16:01.96.
"I just wanted to put together a pretty even swim, hold a good pace,” Ledecky told NBC Sports.
"That one hurt, but I'll take it, move on to Singapore," added the US great, who also won the 400m and a "really good" 800m free this week and finished second in the 200m free.
Ledecky heads to a seventh World Championships aiming to add to her 21 world titles.
"I'm excited," she said. "I mean, I have been to a lot of these, but I still feel like I get the same excitement, the same energy from the team."
Finke won the men's 800m free in 7:43.13, more than six seconds ahead of Rex Maurer.
Finke, who set the men's 1 500m free world record in defending his Olympic title in Paris, also won that event along with the 400m medley – although he has indicated he won't swim the medley in Singapore.
Walsh won the women's 50m freestyle in an American record-equalling 23.91sec to close out a stellar week that saw her win the 100m butterfly with the second-fastest time ever and the 50m fly in the fourth-fastest time ever.
Jack Alexy won the men's 50m free in 21.36, the top time in the world this year.
Santo Condorelli, the 30-year-old who has competed in the Olympics for both Canada and Italy, was second in 21.68 to earn a chance to represent the United States for the first time in international competition.
Shaine Casas won the men's 200m individual medley in 1:55.73, just three-hundredths of a second in front of Carson Foster, Casas notching another victory after his triumph in the 100m butterfly.
Alex Walsh won the women's 100m medley in 2:08.45 with Phoebe Bacon taking second in 2:09.22.