Claire Curzan and Jack Alexy broke their first individual world records at the World Short Course Swimming Championships trials on Friday.

Curzan won the 100m backstroke in 53.92 seconds, breaking fellow American Regan Smith’s world record by one tenth in Westmont, Illinois, where three world records were swum Thursday.

Smith, whose 50m back world record was broken by Katharine Berkoff on Thursday, finished third behind Curzan and Berkoff on Friday.

Curzan and Berkoff made the team for the World Short Course Championships in Beijing’s Water Cube from Dec. 1-6.

Short course meets are held in 25-meter pools rather than 50-meter pools (long course) used at the Olympics and other major meets in the summer.

Curzan, a 22-year-old Virginia senior, added to her list of accolades. She swept the backstrokes at the 2024 World Championships in long course.

The women’s 100m back is shaping up to again be one of the most competitive events to make the U.S. Olympic team.

In long course in 2026, the U.S. had four of the six fastest women in the world (No. 1 Smith, No. 2 Isabelle Stadden, No. 4 Berkoff and No. 6 Curzan). The top two at trials make the team.

Also Friday, Alexy crushed the 100m freestyle world record by two tenths, clocking 44.64. Four weeks ago, Russian Egor Kornev tied Australian Kyle Chalmers’ world record from 2021.

Alexy is the fourth-fastest man in history in the long course 100m free behind three other men who could be at the 2028 Olympics: 2024 Olympic gold medalist Pan Zhanle of China, 2025 World champion David Popovici of Romania and Kornev.

Other winners Friday included Kate Douglass (200m individual medley, three hundredths off her world record), Gretchen Walsh (50m fly, eight hundredths off her world record), Liberty Clark (200m free, American record), Piper Enge (100m breaststroke), Luca Urlando (200m fly, American record), Van Mathias (100m breast, American record), Josh Bey (400m individual medley) and Ryan Erisman (1500m free).

Short course trials finish Saturday, live on Peacock and NBCSN at 7 p.m. ET.