MONTREAL — Michael Phelps has set a new personal best in winning the 100-meter butterfly at the Canada Cup.

His time of 50.48 seconds Saturday bettered his previous best of 50.58 and narrowly missed the world record of 50.40 set by fellow American Ian Crocker at the 2005 world championships.

Phelps is using the Montreal meet as a final tuneup for the U.S. championships, which will serve as the trials for the world championships in Rome next month.