Dhaka, Dec. 7 -- World record-holder Gretchen Walsh clocked 55.60sec to win the 100m butterfly on Friday at the US Open in Austin, Texas, where swim stars Summer McIntosh and Leon Marchand again tested themselves in unfamiliar events.

Walsh's US teammate Regan Smith was second in the 100m fly in 56.18 and Canadian McIntosh produced a personal best of 57.01 to finish third in an event she rarely swims.McIntosh, winner of three gold medals at the Paris Olympics and four titles at the World Championships in Singapore this year, chose to challenge herself in 100m races, foregoing her trademark 400m individual medley.

So did France's Marchand, a four-gold winner in Paris who, like McIntosh, trains in Austin with former Michael Phelps mentor ...