Bubba Watson shot a seven-under-par final-round 64 to clinch victory by two shots in the Northern Trust Open at the Riviera Country Club in California.
The 35-year-old edged out Dustin Johnson and finished 15 under as he claimed his first PGA Tour title since a dramatic US Masters win in 2012.
Fellow Americans Jason Allred and Brian Harman tied for third on 12 under.
England's Lee Westwood, who recently split with coach Sean Foley, shot a final round of 71 to finish six under.
Watson began the day four strokes off the pace but he seized control with five birdies in his first eight holes.
And the left-hander finished the round in style as he rolled in a 14-foot birdie putt at the last to post a total of 269.
Johnson, one of four players who held at least a share of the lead during the final round, closed with a five-birdie 66 to finish alone in second place.
William McGirt, who began the day at the top of the leaderboard in search of his first PGA Tour title, finished five shots off the pace after carding a 73.
South Africa's former Masters champion Charl Schwartzel, the only non-American in the top 10, was fifth on 11 under after he signed for a third consecutive 68.
England's Justin Rose was unable to finish with a flourish as he carded 73 in his final round to finish one under, while it was a similar story for compatriots Ian Poulter and David Lynn who shot 72 and 74 respectively to finish one over.