Masters champion Phil Mickelson posted a 10-under-par course record 62 to open a three-shot first-round lead at the Pebble Beach National Pro-Am.
Mickelson, who won the FBR Open last week, birdied seven of his first 11 holes on the Spyglass Hill course, one of three to be used in the tournament.
American star Davis Love is one of five players in a tie for second, while England's Greg Owen is five under.
World number one and defending champion Vijay Singh carded a disappointing 73.
Mickelson equalled the course record with an 11-under-par 60 in his victory in Phoenix last week and put the success down to his driver.
"I've never driven this well," said the elegant left-hander, winner of this title in 1998.
"To shoot 60 at Phoenix and 62 here, that's what I see paying off.
"I was able to drive it a lot longer than I ever have, have a lot of wedges in and because it's flying the right yardage, I'm able to make a lot more birdies.
"I don't feel surprised right now, normally when I have a very low round I think that's great but it feels like the way I'm hitting it I should shoot that."
European challenge
Mike Weir, the man Mickelson deposed as Masters champion, recovered from a dropped shot at the second at the Poppy Hills course, carding five birdies in seven holes from the fourth en route to a 66 for a share of seventh.
English Ryder Cup star Lee Westwood posted an eventful 68 that included an eagle, six birdies and four bogeys.
He was joined on four under by Northern Ireland's Graeme McDowell, who kept a bogey off his card, while Sandy Lyle began a rare US Tour outing with a level-par 72 containing three birdies and three bogeys, the last of which came at 18.
England's Brian Davis is on three under with Welsh star Phillip Price and Ireland's Paul McGinley. Darren Clarke shot a two-under 70, one better than Ryder Cup team-mate Luke Donald.