Overnight leader Rory Sabbatini held his nerve in the final round of the FBR Capital Open in Potomac, Maryland to shoot another 68 and win the tournament despite a strong challenge from Duffy Waldorf.
Sabbatini finished on 14-under par 270, two shots clear of Duffy Waldorf, and earned $810,000.
Sabbatini's only previous win came three years ago in the Air Canada championship.
Waldorf, who shot 67, could yet incur a two-shot penalty following a possible rules violation on the 12th hole when he tamped down an irregularity in the turf on the fairway as he prepared to play his second shot.
If officials determine that the improved ground was within a reasonable area of his line to the hole, Waldorf would receive the penalty.
Joe Durant and Fred Funk shared third place on 272, four shots behind Sabbatini.
Ireland's Padraig Harrington was at one stage in contention but four bogeys and one double bogey between the 8th and the 18th thwarted his challenge.
The Dubliner had been one shot off the lead after opening with four birdies but his round collapsed after he bogeyed the par four eighth.
Sweden's Niclas Fasth, trailing by a shot when the round began, also self-destructed at the end of the front nine when he double-bogeyed the par-four eighth and triple-bogeyed the par-three ninth to slip for a tie for seventh. Harrington will now travel, a day later than anticipated, to the US Open, which starts Thursday at Olympia Fields Country, Illinois.