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.
Bradley was pleased to shoot a good round a day after golf's ruling bodies said they planned to outlaw the practice of anchoring the putter, which he employs, by 2016.
Asked if that gave him extra motivation, Bradley said: "Yeah, absolutely. I've been catching such flak on Twitter and these other places, it would be good to kind of quiet them a little bit.
"I had a guy yesterday telling me to send my application in to Burger King for 2016. I feel like the USGA (United States Golf Association) has really put an X on our back and I don't know if that's exactly fair.
"When we started putting with it (the belly putter), they were legal, and they still are. It's a sticky situation and I hope people can see through that. It always feels good to play well but this feels better almost."
Woods said: "I didn't hit the ball very good today but made a few good par putts to keep the round going and I kept myself in the tournament. I could have easily shot myself out of the tournament but I kept myself in it."
Are the R&A and USGA right to outlaw the anchoring of putters?