Jordan Spieth outlasted David Hearn and Zach Johnson with a par on the fifth playoff hole on Sunday to capture his first career win at the John Deere Classic.
Spieth birdied five of his last six holes in regulation, including a chip in from a greenside bunker at the 18th, to close out his third straight 6-under 65 and meet 2012 champion Johnson (68) and Hearn (69) at 19-under-par 265.
The 19-year-old American became the first teenager to win a PGA Tour event since 1931.
"Honestly, I don't even know what to say right now," Spieth said after the win.
Martin Flores fired an 8-under 63 during his final round at TPC Deere Run to jump into a share of fourth place with third-round leader Daniel Summerhays (72) and Jerry Kelly (68) at 18-under.
Patrick Reed (67), Matt Jones (68) and J.J. Henry (69) shared seventh at 17- under 267.
Hearn and Johnson each had a pair chances to end the playoff over the first four extra holes.
Johnson had the early chances, just missing holing out a chip shot from off the green at the first playoff hole, and then pushing a potential clinching birdie putt at the second, both played at the 18th hole, to keep the playoff alive.
The next playoff hole was played at the par-3 16th, where Hearn missed about a 15-foot birdie putt for the win to move on to the fourth extra hole.
The fourth was played at the par-5 17th and Hearn lipped out a birdie putt from about five feet to push the trio to the fifth extra hole.
They then returned to the 18th, where Johnson was all but eliminated after hitting his second shot into the water after all three players found the rough with their tee shots.
Spieth found the back fringe with his second shot and was able to 2-putt for the win when Hearn was unable to convert his 7-foot par putt.
"I don't know what I did to deserve those breaks. I said my prayers, I guess," Spieth said about his competitors early mistakes.
Summerhays entered the final round with a 2-stroke lead over Hearn and extended that advantage to three with a birdie at the second, but he would later record four straight bogeys from the fifth to fall behind Johnson, who had four birdies and a bogey over his first eight holes to grab the outright lead at 19-under.
Summerhays bounced back with birdies at the 11th, 13th and 14th to meet Johnson atop the leaderboard, but tripped to another bogey at the 15th to fall a stroke off the pace.
Hearn, meanwhile, played his first 15 holes at 1-under with a pair of birdies around a bogey to remain within striking distance before joining Johnson at 19-under with a 20-foot birdie putt at the 16th.
Spieth used his sizzling closing stretch to also meet them there. He reached the 12th hole at 15-under for the tournament after bouncing back from a bogey at the first with gains at the second, seventh and 10th.
A pair of short birdie putts at the 13th and 14th moved him to 17-under before he tripped to a bogey at the 15th.
But he bounced back with an 11-foot birdie at the 16th that he followed with a 3-foot effort at the 17th. Spieth then hit his second shot at the last into a greenside bunker and was able to bounce his next shot into to cup to join Johnson and Hearn at 19-under.
Johnson briefly grabbed the outright lead with a 2-putt birdie at the 17th, but then made a mess of the 18th after hitting his drive into a bunker and rolling his third shot off the back end of the green en route to a bogey to fall back to minus-19.
Summerhays was in contention for the playoff when his birdie at the 17th also moved him to 19-under, but he needed two strokes to get out of a greenside bunker at the 18th, leading to a bogey to drop him a shot off the pace.
NOTES: Johnny McDermott was the last teenager to win a PGA Tour event when he won the 1911 U.S. Open at the age of 19 years, 10 months and 14 days ... Spieth collected $828,000 for the win ... With the win, Spieth becomes a regular member of the PGA Tour and also earned a spot in next week's British Open ... It was the ninth playoff in tournament history.