The defending champion started slowly Friday, missing birdie and par putts on the back nine, which he played first. He recovered with birdies on his last three holes on the front nine.
"It was like the Pony Express," he told reporters after the round. "You ride it until it drops because you know there are going to be some times when nothing's going to happen right. Everything seemed to happen right today."
David Eger and Mark Wiebe, who won last week's Cap Cana Championship in the Dominican Republic, share second place at 5-under 66, while Scott Hoch, a two-time winner this season, Mark James and Vicente Fernandez share fourth at 4-under 67.
This event features professionals playing with celebrity amateurs for the first two rounds.