Gretchen Walsh Sets World Record in 100m Butterfly at 2024 US Olympic Swimming Trials

American swimmer Gretchen Walsh made history during a semifinal heat at the 2024 U.S. Olympic Swim Trials in Indianapolis.

Walsh clocked 55.18 seconds in the 100-meter women's butterfly Saturday to set a new world record in the event.

Walsh's time beat out Swedish swimmer Sarah Sjöström, who recorded the previous fastest time of 55.48 seconds at the 2016 Olympics in Rio de Janeiro, by more than half of a second.

She said after the event that she was "over the moon" to set the new standard.

"I'm so happy," Walsh said, per NBC. "It's such a surreal experience... I'm trying to convince myself that that just happened, so I'm just in awe."

Walsh entered the semifinal heat as the top seed after recording a time of 55.94 in a preliminary heat. That already ranked as the sixth-fastest race in the event's history, per Yanyan Li of SwimSwam.

Walsh, a Nashville native, is a senior at the University of Virginia who helped UVA become the third swim team in NCAA history to win four consecutive team titles.

The 21-year-old now has the chance to qualify for her first Olympic team if she ranks within the top two finishers during the Sunday night final. She will be competing against experienced Olympians including 2020 Tokyo medalists Torri Huske, Regan Smith and Claire Curzan, the Associated Press' Paul Newberry reported.