Ryan Moore set a course record at Summerlin on Thursday to lead the Justin Timberlake Shriners Hospitals for Children Open after the first round.
The American's round of 61 included eight birdies and an eagle to lead the competition by one shot.
Zimbabwean Brendon de Jonge is a shot further back, with Tim Herron and John Huh in a tie for third place.
After last weekend's Ryder Cup, American captain Davis Love III returned to playing action to shoot a 68 but has work to do if he is to put himself in contention over the weekend.
Erik Compton, who has undergone two heart transplant operations, was closely followed by local fans during his round of 66.
