Bubba Watson held his nerve to beat Webb Simpson in a play-off in the Zurich Classic in New Orleans.
The two Americans, who were overnight leaders, carded final-round 69s to finish on 15 under par, two clear of three players on 13 under.
Watson hit a remarkable approach from over 200 yards from a fairway bunker and two-putted for victory at the second extra hole.
England's Luke Donald fired a 69 to finish tied for eighth on 10 under par.
KJ Choi, the 2002 Zurich winner, shot a 69 to tie for third at 13 under with Jason Dufner (66) and Tommy Gainey (69).
Choi was 14 under after 16 holes, but three-putted for a bogey on the par-three 17th and narrowly missed a birdie putt on 18.
However, the final round was a two-horse race between Watson and Simpson, who duelled for supremacy with some superb shot-making in the first eight holes.
They both eagled the par-five second and were four-under for the day after just five holes.
The tournament appeared to turn decisively at the par-three ninth when Watson found water with a wedge off the tee and returned a double bogey to slip two strokes behind.
Simpson, who reached the turn in four-under 32, then forged three ahead with another birdie at the par-four 10th after an exquisite approach ended up within three feet of the pin.
However, he stumbled with a bogey at the 12th and his lead was cut to one when world number 16 Watson knocked in a four-footer to birdie the 13th.
Simpson suffered another blow at the par-four 15th, where he was given a one-stroke penalty when his ball moved in the wind after he had grounded his putter.
After summoning PGA Tour rules official Gary Young to review the incident, he was penalised and ended up with a bogey five to drop back into a tie for the lead at 15-under.
The next two holes were parred before Watson squandered an opportunity to seal victory with a birdie on 18.
A play-off beckoned and both players birdied the first extra hole, the par-five 18th, before Watson triumphed second time round with a four-foot birdie putt after Simpson missed his own attempt from 12ft.
It was the 32-year-old's third PGA Tour title in 11 months and he said: "A year ago I was a good player who had never won.
"Now I've got three under my belt so it's crazy. It's something that I could never dream of.
"For me to get one was unbelievable. My career was complete. I've done it. Then for me to get another one just adds to my career. It's something I've dreamed about doing."
World number 98 Simpson added: "I hit some good shots coming in and gave myself a chance. Unfortunately, I just came up a little bit short.
"It was fun being out there with Bubba. He's a great friend and a great champion. I'm happy for him. He hit some great shots and great putts coming in."