He carded a 68 to finish at 13-under-par 275, becoming the second Ohio-born player to win the prestigious event after Jack Nicklaus, the tournament's host and founder.
“That’s pretty good company to have,” Dufner said.
A day after shooting a miserable 77 to turn a five-stroke lead into a four-shot deficit on Saturday, Dufner roared back in the final round for his fifth PGA Tour victory.
“Yesterday I was pretty disappointed, especially (after) how well I played the first two days,” he said in a greenside interview after being congratulated by Nicklaus.
“I thought I was in control (after 36 holes and) I had to get over it quick. There’s a lot of things that can happen and I knew I was still in the mix.
“I just needed to get myself together. Making the turn even was good and then I felt comfortable to get a little aggressive on the back.”
Dufner's victory was not as comfortable as the final margin might suggest.
He had to wait out a weather delay of more than an hour after his drive had settled into thick rough at the par-four 18th. His lie was so bad that when play resumed he could not even scythe a wedge back to the fairway.
However, his ball found a better lie in lighter rough and he punched his third shot to the middle of the green.
While there was no pressure on the long putt, Dufner sank it anyway.
“The 30-footers are a little easier than the three-footers apparently,” he joked.
Fowler, meanwhile, bogeyed the last to shoot 70 and ended up tied for second with Lahiri, whose 65 was the day's best score.
Overnight leader Daniel Summerhays double-bogeyed the last to finish six shots behind after a 78.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Ian Ransom/Peter Rutherford)
