La Jolla - Australia's Jason Day parred the second hole of a four-man sudden-death playoff on Sunday to win the $6.3 million Farmers Insurance Open at Torrey Pines.
With his third US PGA Tour triumph, the 27-year-old Day will rise from eighth to number four in the world, overtaking Adam Scott to become the top-ranked Australian.
He out-lasted JB Holmes - who fell short with a bogey at the second playoff hole - and defending champion Scott Stallings and Harris English - both eliminated at the first extra hole.
"It's an amazing feeling because I've been working so hard for this. I just kept visualizing myself holding the trophy this week, kind of like what I did at the (WGC) Match Play," Day said. "I just said, I'm not going to stop, I'm not going to stop.
"I'm just really proud of myself to be able to hang in there and grind it out."
Day's tee shot at the second extra hole, the par-three 16th on the Torrey Pines South Course, flew straight over the flagstick and left him a long birdie attempt.
His putt went right, but left him a tap-in for par.
Holmes, meanwhile, flew the green and after chipping on was unable to convert his par attempt.
Day, Holmes, Stallings and English all finished 72 holes on nine-under 279. Day carded a final-round 70, Stallings a 69 while Holmes and English, who shared the overnight lead, carded even-par 72s.Day had a bit of luck just to make the playoff. His chip from behind the green at 18 in regulation was rolling briskly toward the water hazard, but stopped just short of the hazard line and he closed with a par.
He had put himself in contention with birdies at 15 and 16 - where he drained a 47-footer.
"I had a great save at 17 from a plugged lie in the bunker," Day said. "Then, learning from my mistake on 18 and taking that into the playoff... the hard work is paying off."
The foursome returned to the par-five 18th to start the playoff. All four reached the green in regulation. English rolled his long birdie effort within a foot of the hole and he tapped in for par.
Stallings followed with his birdie try from about 15 feet out, and he missed left.
Holmes had played his third shot to three feet and he converted that for birdie. Day, who shared second place at this event last year, rolled in his short birdie putt to extend the playoff.
Alex Prugh with a 71 and Charles Howell with a final-round 68 shared fifth place on 280, one stroke in front of Scotland's Martin Laird, Ireland's Shane Lowry and Americans Nick Watney and Jimmy Walker.
The biggest names in the field didn't make it to the weekend.
Former world number one Tiger Woods limped off with back trouble after 11 holes of the first round on Thursday and five-time major champion Phil Mickelson missed the cut.Leading final-round scores on Sunday from the $6.3 million US PGA
Tour Farmers Insurance Open (x-won at second playoff hole, USA unless
279 - x-Jason Day (AUS) 73-65-71-70, JB Holmes 69-70-68-72, Scott Stallings 70-72-68-69, Harris English 68-66-73-72
280 - Charles Howell 72-70-70-68, Alex Prugh 70-70-69-71
281 - Martin Laird (SCO) 68-68-76-69, Shane Lowry (IRL) 74-67-72-68, Nick Watney 71-65-72-73, Jimmy Walker 72-66-70-73
- Zac Blair 72-70-71-69, Michael Thompson 65-73-74-70, J.J. Henry
68-71-73-70, Carlos Ortiz (MEX) 73-70-68-71, Jhonattan Vegas (VEN)
67-69-73-73, Spencer Levin 68-70-70-74
283 - Colt Knost 69-72-71-71, Chad Collins 75-66-75-67
- Jamie Donaldson (WAL) 72-71-69-72, Brandt Snedeker 70-71-71-72, Ian
Poulter (ENG) 67-71-72-74, Bill Haas 72-67-70-75, Chad Campbell
285 - Daniel Berger 70-68-77-70, Tony Finau 73-68-70-74, Lucas Glover 70-68-70-77
- Brendon de Jonge (ZIM) 67-72-73-74, Camilo Villegas (COL)
70-70-75-71, Marc Leishman (AUS) 72-66-72-76, John Peterson 68-72-70-76,
Andres Gonzales 69-69-71-77