Matt Kuchar produced a blemish-free seven-under-par 64 to lead by one on the first day of the Northern Trust Open in California.
Kuchar began his round with three successive birdies and picked up four more along the way to claim a one-shot lead over Spain's Sergio Garcia.
"It's always fun to have bogey free days, especially around this golf course," Kuchar said on www.pgatour.com. "I just drove it well today which is a big key around here.
"The greens are pretty tricky and pretty firm this year, so coming out of the rough, it's difficult to get a ball to stop close to the hole.
"Coming out of the fairway is a key thing to play some good golf, so we are driving it well and I played some nice golf today."
Starting at the 10th, Garcia also picked up shots on his first three holes and would have sat alongside Kuchar at the head of the field but for a bogey at the 13th.
One shot behind Garcia on five under was Brandt Jobe, with a group of three men on four under headed by England's David Lynn.
Last year's runner-up at the PGA Championship is hardly one of the star names in a high-quality field this week, but he was right in the mix in a share of fourth alongside James Hahn and Charlie Beljan.
He began his day with a birdie on his opener at the par-four 10th.
The 39-year-old picked up further strokes at two of the three par-fives before birdies at the third and fifth had him on course to keep pace with Kuchar.
A bogey at the par-four seventh slowed Lynn but he maintained his position to go into the clubhouse three shots adrift.
Lynn was the standout performer on a good day for the British contingent.
Lee Westwood was three under, Luke Donald and Greg Owen two under and Brian Davis was one under.
There was less good news for Ross Fisher, who was one over, Graeme McDowell (two over), and Martin Laird (three over), while three-time major-winner Padraig Harrington of Ireland had a day to forget as carded to bogeys and two doubles to finish six over.
Defending champion Bill Haas was in the mix on one under.
Play ended with 18 men yet to complete their rounds because of fog and darkness.