All that separated Jason Dufner from winning the PGA Championship Sunday was a 4-iron. A very poor 4-iron.

Unfortunately, it came on No. 16, the 70th hole of the championship, when he was nursing a three-shot lead.

"The one I want back is probably 16 more than anything," he said afterwards.

Dufner's 4-iron approach from 213 yards found a greenside bunker on the right, dangerously close a right-side pin placement. Dufner splashed out but missed the slick downhill par putt. He made bogey and saw his lead chopped to 2 strokes.

Had he hit the green -- and he led the tournament in greens in regulation (79.17 percent) -- Dufner likely would be the one partying with the Wanamaker Trophy. Instead, he made bogey, followed it with a three-putt bogey on No. 17 and eventually lost a playoff to Keegan Bradley at the Atlanta Athletic Club.

"One of the worse iron shots I hit all week," he said.

His slide may have actually started a hole earlier. Over the first three rounds, Dufner played the final four holes in 3 under. Standing on the 15th tee, he had 5-shot lead over Bradley, who just tripled-bogeyed the hole, and four-shot lead over the field.

In between clubs on the 259-yard hole, he tried to hit a 5-wood. It started on the line he wanted, but the ball never drew, dropping in the water.

That bogey was followed by two more and in short order, he dropped from 11 under to 8 under and into a playoff with Bradley, who had birdied 16 and rolled in a 35-foot birdie putt on 17 to overcome a triple bogey on No. 15.

Dufner, who has never won a PGA Tour event much less a major, regrouped and opened the three-hole playoff by slamming his drive down the middle of the fairway on No. 16. He then nearly holed out his 5-iron from 185 yards away. Stone-faced all week, he finally showed some emotion, briefly throwing up his arms as he walked up the fairway.

That joy didn't last long.

Bradley dropped his approach shot practically on top of Dufner's, both ending up within the length of the flagstick's shadow as the sun began to drop through the pines.

Dufner was left with a 6-foot downhill putt that was similar to the one he missed in regulation. Dufner said he missed his line by a half-inch and the putt dove left, away from the hole. He made par. Bradley dropped in his four-footer for birdie and one-stroke advantage.

"Maybe there was a little pressure he put on me, I guess," Dufner said. "We are both in a situation that we both know that we need to make those putts to win these tournaments."

Both hit the par-3 17th green. Just as he did in regulation, Dufner rolled his birdie putt past the hole, this time by 20 feet. Just like he did in regulation, he missed the par come-back putt.

"You'd think second time around I might be a little bit better but I was worse," he said.

Dufner was surprisingly upbeat afterward and not because as runner-up, he just made $865,000 and earned a spot in all four majors next year. Though few golf fans, outside those who might follow him because he went to Auburn, have ever heard of him, he doesn't plan on disappearing into history like so many others who have come close and failed.

"You know, maybe looking back 10, 15 years from now I'll feel disappointment that I let this one get away, if I never get another chance," he said. "But I've got a feeling that I'm going to have some chances to win some majors."