Tom Scherrer fired a four-under-par 67 to capture the PGA Kemper Open by two strokes, becoming the ninth player to win his first Tour title at this event.
The 29-year-old American finished at 13-under-par on 271 to claim the $540,000 top prize at the Potomac course in Maryland.
Scherrer birdied the 10th, 11th and 14th holes and sank a crucial 10-foot par-putt on the 15th to break from a quintet of contenders on the back nine.
Steve Lowery, who led after each of the first three rounds, bogeyed the 15th and 17th holes to finish second, alongside Kasuhiko Hosokawa, Justin Leonard, Greg Chalmers and Franklin Langham.
Australian Stewart Appleby, the 1998 winner here, made a run within one stroke of the lead with birdies on the 13th and 14th.
But Appleby finished with three pars and a bogey to fall back to share seventh.
American Michael Clark birdied the final hole to equal the course record with an eight-under-par 63 to finish at 279.