Nick Watney won his second PGA Tour title of the season with a two-shot victory in the AT&T National in Pennsylvania.
The 30-year-old from California shot a closing bogey-free, four-under 66 to hold off the challenge of Korean KJ Choi at Aronimink.
Choi made a charge on the back nine and caught Watney with a 35-foot birdie putt on the 14th. But on the next hole, Choi made double bogey six after getting a plugged lie in a bunker and firing his third shot through the green.
Both men birdied the par five 16th and two pars on the closing holes were enough to earn Watney the victory, his fourth in six years on the PGA Tour.
Watney won the WGC-Cadillac Championship earlier this year and has gone top of the FedEx Cup standings, ahead of Choi who moves up to second above England's Luke Donald.
Watney had a course-record eight-under par round of 62 on Saturday, to earn a share of the lead alongside his fellow American Rickie Fowler heading into the final round.
He was never headed, but Fowler is still looking for his first win after slipping away with a closing 74 to finish in a tie for 13th.
Defending champion Justin Rose was the top European finisher, the Englishman's closing 69 moving him up into a share of 15th place.