Rory McIlroy shot a four-under-par 67 but it was not enough to overhaul winner Jacob Bridgeman, who won by one shot at the Genesis Invitational in Los Angeles.
Northern Ireland’s McIlroy started the day six shots off the lead but despite making five birdies he could not catch American Bridgeman, who got over the line with a one-over-par 72 to finish on 18 under.
Bridgeman, who held a seven-shot lead early in the day, held back tears on the 18th green before sinking a three-foot putt for his first PGA Tour title.
He is also the first man to win the prestigious event in his tournament debut since 1975.
Bridgeman’s victory continues his good start to the year having had two top-10 finishes in his opening four events, including last week’s eighth place at Pebble Beach.
The 26-year-old’s three bogies on the final day at the Riviera Country Club gave the chasing players hope, including countryman Kurt Kitayama, who finished tied for second with McIlroy on 17 under after carding a seven-under-par 64.
World number two McIlroy was even par after the first nine holes, but made four birdies on the back nine, including a brilliant hole-out from the greenside bunker on the 12th, to put pressure on Bridgeman.
A nervy closing three holes saw Bridgeman bogey 16 then leave his putt on 18 over three feet short, after McIlroy had drained a 30 footer to get within a shot, to ensure a tense final stroke in front of tournament host Tiger Woods.
Bridgeman held his nerve though to claim a first PGA Tour title in style, with victory at one of the Signature Events moving him inside the top 25 of the world rankings for the first time.
England’s Tommy Fleetwood shot a four-under-par 67 to finish joint-seventh on 12-under, which included a slam dunk eagle with his approach shot on 15 from 173 yards out.
World number one Scottie Scheffler made a flying finish with his 65 seeing him recover from his bad start on Thursday to finish in joint 12th.
That meant an end to Scheffler’s brilliant run of 18 consecutive top-10 finishes on the PGA Tour.
England’s Marco Penge, who was the joint-leader alongside Bridgeman after the second round, ended in tied for 16th place on 10 under.
Max Greyserman provided another big highlight of the day as he made a hole-in-one at the 14th, which illuminated an otherwise difficult day for him as he made four bogeys and a double bogey in his 73.