The 21-year-old from Nashville, Tennessee, shaved 0.32 seconds off the previous record, held by Sweden’s Therese Alshammar since 2009. Alshammar's mark of 24.38 was set at the Swimming World Cup in Singapore, a record that stood unchallenged for an astonishing 5,498 days—until Walsh's morning swim in Budapest. The performance also added the 37th World Record to the storied history of the Duna Arena in Hungary’s capital.

Competing in the fifth of six heats, Walsh’s powerful underwaters proved decisive in her record-setting performance. Already a double Olympic gold medallist in relays at the Paris 2024 Games and a three-time medallist at the 2023 World Aquatics Championships, Walsh is showing she’s just as dominant in her first appearance at a short-course World Championship.

Walsh will have two more opportunities to push the record even further, with the Women’s 50m Butterfly Semi-Finals scheduled for tonight and the Finals set for Wednesday, 11 December.