Miami - South Korea's Im Sung-jae captured his first PGA Tour title on Sunday in a dramatic four-man Honda Classic shootout, then shared his worries about the coronavirus outbreak striking his homeland.

The 21-year-old Asian prodigy, last year's PGA Rookie of the Year, birdied four of the first five holes and sank tension-packed birdie putts at the par-3 15th and 17th to help secure the victory at Palm Beach Gardens, Florida.

Im fired a four-under par 66 final round to become the youngest winner in tournament history with a breakthrough triumph at PGA National in his 50th PGA start.

"After so many chances so many weeks and having a bunch of top 10s, using that experience this week was big," Im said through a translator. "I hope to really work hard and move forward and become a winner again soon."

Im finished 72 holes on six-under 274 for a one-stroke victory over Canada's Mackenzie Hughes. Britain's Tommy Fleetwood was third on 276 and American Brendan Steele shared fourth on 277 with England's Lee Westwood, American Daniel Berger and South Korean An Byeong-hun.

After the breakthrough title, Im expressed his concern over the coronavirus and its impact in South Korea.

"There have been reportedly over 2 000 cases of the coronavirus in South Korea and I'm a little concerned and worried about how fast this virus is spreading," Im said through a translator.

"All I can do is pray for the best and hope moving forward that not many more people get infected and hopefully this virus can be calmed down and sort itself out."

Im made a huge drive over water to eight feet at the par-3 15th and sank the putt to create a four-man logjam atop the leaderboard with Fleetwood, Hughes and Steele.

Hughes sank a stunning 53-foot birdie putt at the 17th to briefly match Im for the lead, but the South Korean calmly answered moments later with a birdie putt from just inside eight feet to reclaim the solo lead for good.

England's Fleetwood, runner-up at the 2018 US Open and 2019 British Open and seeking his first US PGA victory, sank a 24-foot birdie putt at 17 to pull within one of Im heading to the par-5 18th with Steele two back.

Fleetwood and Steele both plunked their second shots into the water at 18 to doom their title hopes while Hughes pulled his approach left into the grandstand, recovering for a par but settling for second place.

Im made aggressive shots on the closing holes to set up his birdies, knowing the event was up for grabs.

"I knew I was one back going into the last four," Im said. "I wanted to get a little more aggressive than I had been playing on the final holes. I felt pretty good after the birdie."

Im said his performance for the Internationals in last December's Presidents Cup, when he went 3-1-1, helped him handle the intense pressure he faced in the final round.

"I felt a little less pressure than I did at the Presidents Cup," Im said. "Hopefully that can help me going forward."

Hughes, whose last top-10 effort was nine months ago at Colonial, shared the lead at 16 but missed the fairway with his approach and was just short on a 22-foot par putt.

Im found a fairway bunker but blasted out with a 5-iron from 176 yards and two-putted from 28 feet for a key par.

At 18, Im layed up on his second shot out of the rough only to find a bunker with his third, but blasted his 60-foot bunker shot two feet beyond the hole and made the putt.

Leading scores after Sunday's final round of the PGA Tour Honda Classic at PGA National in Palm Beach Gardens, Florida (USA unless noted, par-70):

274 - Im Sung-jae (KOR) 72-66-70-66

275 - Mackenzie Hughes (CAN) 71-72-66-66

276 - Tommy Fleetwood (ENG) 70-68-67-71

277 - An Byeong-Hun (KOR) 76-66-68-67, Daniel Berger 69-70-69-69, Lee Westwood (ENG) 67-69-71-70, Brendan Steele 68-67-71-71

278 - Gary Woodland 70-67-74-67, Cameron Davis (AUS) 70-67-73-68, Russell Henley 70-69-70-69

279 - Brice Garnett 72-69-72-66, Wyndham Clark 68-74-71-66, Maverick McNealy 70-69-71-69, Robby Shelton 70-69-70-70, Mark Hubbard 69-71-69-70, Luke Donald (ENG) 70-66-71-72

280 - Harris English 66-74-72-68, Richy Werenski 70-68-73-69, Ryan Palmer 70-72-68-70, Charl Schwartzel (RSA) 69-69-70-72

281 - Hudson Swafford 70-69-73-69, Patrick Rodgers 69-71-72-69, Kramer Hickok 73-70-69-69, Shane Lowry (IRL) 69-69-73-70, Jimmy Walker 72-69-70-70, Brandon Hagy 70-71-69-71