The United States set the world record in the 4×100 mixed relay on Saturday, clocking 3 minutes, 18.48 seconds in the 2025 World Aquatics Championships in Singapore.
The old record was 3:18.83 set in 2023 by Australia.
Vincent Thian / AP 
It was only the second world mark set in these championships. It came on a night when the United States won three gold medals, by far its best performance in what had been a lackluster championships for the team.
Katie Ledecky won the 800 freestyle and Gretchen Walsh took the 50-meter butterfly. The Americans now have eight gold medals. The championships close on Sunday.
Despite the relay gold, the story was Ledecky remaining unbeaten in the 800 freestyle. She first won that race in the 2012 Olympics and has never lost since in a major competition.
OLI SCARFF/AFP via Getty Images 
After 700 meters, 18-year-old Summer McIntosh of Canada was slightly ahead but she faded and Ledecky won in 8:05.62, with Lani Pallister of Australia taking silver (8:05.98), with bronze for McIntosh (8:07.29).
McIntosh has won three individual gold medals in Singapore and was trying for five. She will come up short, though she will be the favorite in Sunday’s 400 individual medley.
Ledecky said she was not aware she was trailing. She glanced down at a race results sheet to confirm it.
“I didn’t know,” she said. “I just knew it was close the whole way. There were times where I thought I was just going to break away. I was just happy I was up there.”
“You just never know when you dive what everyone’s tactics are going to be — or what’s going to happen,” she added. “It was fun to just be in that kind of a race. Just try to make small moves just here and there.”
Ledecky has won 23 gold medals at world championships and 30 overall. Add to that nine Olympic gold medals and 14 Olympic medals overall. If you’re counting, that’s 44 Olympic and world medals.
In other results
Gretchen Walsh of the United States won the 50 butterfly in 24.83 seconds for her second individual gold of the worlds. She won the 100 fly. Alexandria Perkins of Australia claimed silver (23.51) with bronze for Roos Vanotterdijk of Belgium (25.43).
Lee Jin-man / AP 
“It feels great to be like myself again in the water after kind of a rocky week,” said Walsh, referring to the ” acute gastroenteritis ” that the Americans have battled in Singapore following a training camp in Thailand.
“Two-time world champion. Can’t complain with that,” Walsh added.
Paris Olympic 50-fly gold medalist Cameron McEvoy of Australia repeated his title in the worlds, winning in a quick 21.14. Ben Proud of Britain was the silver medalist (21.26) and American Jack Alexy took bronze (21.46).
Defending champion and world-record holder Kaylee McKeown of Australia won gold again, taking the 200-meter backstroke in 2:03.33. American Regan Smith took her fourth silver medal in Singapore (2:04.29) with bronze for American Claire Curzan (2:06.04).
Maxime Grousset of France picked up his second gold, taking the 100 butterfly in 49.62, just off the world record of 49.45 by American Caeleb Dressel. Noe Ponti of Switzerland took silver (49.83) with bronze for Canadian Ilya Kharun (50.07). Grousset also won the 50 fly.