RIO GRANDE, Puerto Rico, March 10, 2013 (AFP) - The 29-year-old Brown, who got into the tournament on conditional status after finishing 148th on the PGA Tour money list last year, birdied the last for the win to finish at 20-under 268.
Gomez appeared to be heading to victory with a one stroke lead entering the last hole when the wheels suddenly fell off at the Trump International Golf Club course.
He made bogey on the par-five 18 to finish with one-under 71 on the day.
With his first career victory on the tour, the American has his playing card back and a spot in the PGA Championship later this year.
Gomez tied for second place with 19-year-old Jordan Spieth at 19-under. Spieth shot a 67.
Final scores on Sunday after the fourth round of the $3.5 million PGA Tour's Puerto Rico Open (USA unless noted, par 72):
268 - Scott Brown 68-63-67-70
269 - Jordan Spieth 69-66-67-67, Fabian Gomez (ARG) 69-64-65-71
270 - Justin Bolli 67-69-68-66, Brian Stuard 67-69-66-68
271 - Andres Romero (ARG) 65-65-75-66, Peter Uihlein 67-65-72-67
272 - David Hearn (CAN) 68-67-71-66, D.J. Trahan 72-65-69-66, Boo Weekley 71-67-66-68
273 - Dicky Pride 68-67-72-66, Robert Streb 71-65-70-67, Brendon de Jonge (ZIM) 70-69-65-69
274 - Cameron Percy (AUS) 65-70-71-68, Vaughn Taylor 69-68-69-68, Morgan Hoffmann 67-68-68-71, Matt Jones 71-69-64-70