Rory McIlroy is four shots off the lead after the Genesis Invitational opening round in his first tournament since returning as world number one.
The Northern Irishman, back on top of the rankings for the first time in five years, carded a three-under-par 68 that included two eagles in California.
American Matt Kuchar holds a three-shot lead on seven under par.
Tournament host Tiger Woods is on two under alongside Brooks Koepka, who McIlroy replaced as world number one.
Woods, seeking a record 83rd PGA Tour victory, made a 25-foot eagle putt at the first but bogeyed the last at Riviera Country Club.
McIlroy, 30, started from the 10th tee and also eagled the first hole as he played his back nine in three under, having made two bogeys before the turn.
England's Paul Casey and Justin Rose are a further stroke back on two under.
The PGA Tour event at Pacific Palisades in Los Angeles sees nine of the world's top 10 players taking part.