Los Angeles - Sebastian Munoz parred the first playoff hole on Sunday at the Sanderson Farms Championship to beat Im Sung-jae and earn his first PGA Tour victory.
Munoz birdied the last hole in regulation to force the playoff, then returned to 18, where he rolled in a four-foot putt to pull out the victory over the 2019 tour rookie of the year.
"I am speechless. This is crazy," said Munoz, who becomes just the second Colombian to win on the tour, joining Camilo Villegas.
"The putts weren't going in but I just stayed confident. It was awesome."
The 26-year-old Munoz fired a closing round of two-under par 70 for an 18-under 270 total to tie Im, who closed with a 66 on Sunday at The Country Club of Jackson in Mississippi.
Im's South Korean compatriot An Byeong-hun finished in third, one shot back of the leaders, after a 69 in the fourth round.
Munoz's three prior professional wins have all come in Colombia - including the 2016 Colombia Championship on the developmental Korn Ferry Tour. He was coming off a tie for seventh at The Greenbrier last week.
Munoz, who started the fourth round with a one-shot lead, becomes the seventh first-time tour winner of this event in the past eight years.
The last time Munoz had a 54-hole lead he finished tied for third at The Greenbrier in 2017.
On the playoff hole, both players landed in the rough, on either side of the fairway off the tee.
Hitting out of the left-side rough, Im flew his second shot over the flag stick and into the grandstand.
That opened the door for Munoz, who had found the right rough off the tee. But Munoz left his 166-yard second shot well short of the green.
Munoz then made a nice chip to four feet and claimed the victory after Im missed badly from six feet on his first putt.
Munoz had birdies in regulation on three, 11 and 18 and a bogey on 15. He forced the playoff by making a slow roller from 15 feet over an uphill slope.
"We decided on a line and tried to make it as simple as we could," he said of the clutch putt.
Munoz is the second South American in as many weeks to win after Chile's Joaquin Niemann captured his first title by six shots at The Greenbrier.
"Jaco's win gave me the belief I needed, the little extra belief I'm good enough," said Munoz.
Munoz, from Bogota, was in the final group with his former teammate at the University of North Texas, Carlos Ortiz, but the Mexican needed an eagle on 18 to get into the playoff and settled for a par.
Ortiz shot a final-round 71 to finish in a tie for fourth with American Kevin Streelman at 272, two shots back of Munoz and Im.
Im's burgeoning career gathered more steam as he charged to the finish with three straight birdies on 14, 15 and 16 to get to 18 under overall.
Like Munoz, the 21-year-old Im was gunning for his first tour title after winning the 2019 rookie of the year award. His best previous finish was a tie for third at the Arnold Palmer Invitational in March.
Defending champion Cameron Champ shot a two-under 70 and finished in a tie for 28th.
Leading scores after Sunday's fourth round of the US PGA Tour Sanderson Farms Championship at Jackson, Mississippi (x-won on first playoff hole, par-72, USA unless noted):
270 - x-Sebastian Munoz (COL) 70-67-63-70, Im Sung-jae (KOR) 68-69-67-66
271 - An Byeong-hun (KOR) 66-66-70-69
272 - Carlos Ortiz (MEX) 65-71-65-71, Kevin Streelman 72-67-69-64
273 - Dylan Frittelli (RSA) 71-69-67-66, Bronson Burgoon 69-69-70-65, George McNeill 67-67-70-69, Harris English 65-71-68-69, Dominic Bozzelli 70-67-67-69
274 - Cameron Percy (AUS) 65-70-68-71, JT Poston 64-70-70-70, Lanto Griffin 71-67-70-66
275 - Zach Johnson 67-71-68-69, Brian Harman 71-69-68-67
276 - Cameron Tringale 70-68-69-69, Scottie Scheffler 68-66-72-70
277 - Fabian Gomez (ARG) 72-66-69-70, Zack Sucher 69-69-70-69, Richy Werenski 69-68-70-70, Denny McCarthy 69-71-69-68, Garrett Osborn 70-67-71-69