Richy Werenski made three birdies and an eagle over Sunday's final seven holes to chase down fellow American Troy Merritt and win the Barracuda Championship for his first PGA title.
The unique event uses a Modified Stableford scoring system that awards points for birdies, eagles and all sub-par scores but subtracts points for bogeys and worse with no points for par.
Merritt reached 38 points with a birdie at the eighth but finished with 10 consecutive pars, coming up short on a 30-footer for a 2-point birdie at 18 that would have given him the triumph.
Werenski closed with birdies at the par-5 12th and par-4 14th, an eagle at the par-4 16th and a birdie on 18 to complete an 11-point run that edged him into the final victory margin of 39-38.
"It's huge," Werenski said. "I've been playing well the past couple of months but to win is huge. It helps my confidence a lot."
Austria's Matthias Schwab and Argentina's Fabian Gomez shared third on 37 points after 72 holes at Old Greenwood course at Tahoe Mountain Club in Truckee, California.
Werenski, who lost a three-man playoff for the 2017 Barracuda crown, won his way into next week's PGA Championship at TPC Harding Park in San Francisco.
Merritt and Werenski both earned berths into next month's US Open at Winged Foot in suburban New York.
"Hit a lot of quality shots. Just couldn't find a birdie on the back side," Merritt said. "I gave it my best and came up one point short."