Los Angeles - Daniel Berger fired a four-under-par 66 to retain his St Jude Classic crown in Memphis on Sunday, emerging from a crowded field to claim the second PGA tour win of his career.
The 24-year-old from Florida, who started the day at TPC Southwind three off the pace, carded four birdies and 14 pars to finish on 10 under 270.
South Africa's Charl Schwartzel and South Korea's Kim Whee finished a shot adrift on 271.
A cluster of five players, including overnight co-leader Rafa Cabrera Bello of Spain, were one shot back on 272.
A playoff had appeared to be looming in the closing stages until Berger produced a superb birdie on the par-four 15th.
After making the green in two, he rolled in a long birdie putt to edge one shot clear of the field. He then played flawlessly over the final three holes to take his lead in the clubhouse.
But even with several groups still to finish, no-one looked like threatening Berger's lead to leave him celebrating a win he had never dreamed of.
"Golf is tough. There's ups and downs, but I just can't believe that I've won again," he said afterwards, revealing that he had followed the same routine this year as he had done last season.
"I'm staying in the same hotel room, exact same room number that I was last (year)," he said. "I thought there was no chance this could be my week, but apparently it was.
"I'm extremely proud. I'm 1-for-1 defending titles, so that's a pretty good stat. I just battled so hard today and played so good. I just can't be happier."
Leading scores after the final round Sunday in the PGA Tour St Jude Classic at TPC Southwind in Memphis, Tennessee (Par 70; USA unless noted):
270 - Daniel Berger 70-68-66-66
271 - Charl Schwartzel (RSA) 65-66-74-66, Kim Whee (KOR) 69-66-69-67
272 - Chez Reavie 66-65-72-69, Billy Horschel 72-66-70-64, Braden Thornberry-a 71-69-67-65, Kevin Chappell 68-67-68-69, Rafa Cabrera Bello (ESP) 70-66-65-71
273 - Phil Mickelson 69-67-69-68
274 - Harris English 67-72-70-65, Steve Wheatcroft 68-69-69-68, Adam Scott (AUS) 71-64-71-68, Dominic Bozzelli 69-67-69-69, David Hearn (CAN) 70-67-67-70, Chad Campbell 67-69-66-72, Stewart Cink 64-68-69-73, Ben Crane 68-65-68-73
275 - Grayson Murray 67-72-69-67, Trey Mullinax 68-66-72-69, Joel Dahmen 70-66-69-70, Fabian Gomez (ARG) 69-69-67-70, Matt Jones (AUS) 65-69-69-72, Luke List 70-66-66-73