Watney two ahead at Sherwood
Nick Watney's five-under 67 gave him a two-shot lead after the opening round of the World Challenge event.
The American started with eight straight pars before a birdie at the ninth sparked him into life.
He added four more birdies on the way home - at the 13th, 14th, 16th and 18th - to complete the only bogey-free round at the 18-man invitational tournament, which is hosted by Tiger Woods at Sherwood County Club in Thousand Oaks, California.
Watney's form was in stark contrast to his performance at the same tournament last year when he finished dead last on 11-over-par for his four rounds.
Northern Ireland's Graeme McDowell, who won this event two years ago, made a promising start with a 69 to sit alongside Americans Keegan Bradley and Jim Furyk in a share of second place on three under.
And world number two Woods is himself well placed after trading three birdies with a solitary bogey in a round of 70.
Bo Van Pelt and Webb Simpson matched Woods' effort to make it an American trio on two under.