Eight extra holes were needed to split Harris English and Kramer Hickok at the Travelers Championship with English sealing his second play-off this season.
Hickok went into the final round in Connecticut as joint leader and picked up two shots before the turn. He then mixed two birdies and a bogey on the back nine for 67 and 13 under for the tournament.
English saved his best for last, following a 67-68-67 with a Sunday 65 which could have been a 64 had a 28 foot putt for par on the 17th found the hole.
The Americans went into a play-off in Cromwell with both players matching each other par-for-par in five visits to the 18th and two to the 17th before English holed a five-foot birdie putt to seal the title.
"Kind of sorry it took seven or eight holes, but we were both grinding," English said afterwards. "Kramer is a hell of a competitor. We were both fighting to the end and that's what you want."
The only longer sudden death play-off in PGA history was when Lloyd Mangrum and Cary Middlecoff were declared co-winners after 11 play-off holes due to darkness in the 1949 Motor City Open.
The sudden death play-off was the longest on the PGA Tour since John Huh defeated Robert Allenby in another eight-hole play-off at the 2012 Mayakoba Golf Classic in Mexico.
"It was a huge learning experience for me," Hickok said. "It was just a tremendous day. I mean, it was just a hard-fought battle out there. Played tough. Kudos to Harris. He battled so hard.
"There were times I put him in a tough spot, he put me in a tough spot, and he came out on top and he's a true champion."
Australian Marc Leishman finished third, jumping 14 places up the leaderboard with a final round of 64 to finish a shot behind English and Hicock, while Ireland's Seamus Power tied for 19th on seven under.