Shaine Casas Pops Personal Best in 100 Butterfly at U.S. Open

U.S. Open, Day Three Finals (Men): Shaine Casas Pops Personal Best in 100 Butterfly

Thanks to a career-best performance from Leon Marchand in the 400-meter freestyle and a personal-best mark from Chris Guiliano in the 50 freestyle, the first full night of men’s competition at the U.S. Open was impressive on Thursday night. Will the fast performances continue?

Friday night’s competition will feature Guiliano and Luke Hobson as the top seeds in the 200 freestyle and Shaine Casas and Ilya Kharun will be in the middle lanes for the 100 butterfly. Casas and Kharun each dipped under the 51-second barrier during the preliminaries, with Casas going a championship record of 50.78.

Here is an event-by-event recap of the Night Three finals:

Results
Day One Finals
Day Two Finals

Men’s 100 Butterfly

Entering the final of the 100 butterfly, Shaine Casas sat 11th in the history of the event. He’s now No. 9, following a career-best performance of 50.24. Casas led wire-to-wire, covering the front half of the race in 23.22 and coming home in 27.02, splits which allowed the Team USA veteran to improve on his previous best of 50.40. He was followed in second place by Canadian Ilya Kharun, who touched in 50.40.

Third place was secured by Leon Marchand, the four-time Olympic champion who is racing several secondary events during the U.S. Open. Marchand turned in a performance of 51.20, a personal best by more than a second.

Men’s 400 Individual Medley

Carson Foster gave his personal best a nudge in the final of the 400 individual medley, producing a winning time of 4:07.02. Foster wasn’t far off his best effort of 4:06.56 and now ranks No. 2 in the world for the 2025 campaign. Forced to withdraw from the World Championships due to injury, Foster’s performance sends him into the 2026 season with momentum. He was followed in second place by Baylor Nelson and Luka Mijatovic, who touched in matching times of 4:15.91.