Published: Aug 14, 2011 7:48 PM EDT
Updated: Aug 15, 2011 6:30 AM EDT

JOHNS CREEK, Georgia (AP) - In a PGA Championship filled with unfamiliar names at the top of the leaderboard, Keegan Bradley delivered an unforgettable finish.

Bradley was five shots behind with only three holes to play Sunday after his chip shot raced across the 15th green and into the water, leading to a triple bogey. That's when he reminded himself that no lead was safe on the final four holes at Atlanta Athletic Club.

"I just kept telling myself, 'Don't let that hole define this whole tournament,'" Bradley said.

Instead, it led to one of the most stunning turnarounds in a major. Bradley made back-to-back birdies, including a 35-footer that rattled into the cup on the 17th.

Then came a monumental meltdown by Jason Dufner. Unflappable all afternoon, he hit his tee shot into the water on the 15th for the first of three straight bogeys that led to a three-hole playoff.

Bradley birdied the 16th hole in the playoff - his first outright lead of the day - and went on to win by one shot.

After his victory, Bradley took a picture of the oversized Wanamaker Trophy with his mobile phone and posted it on Twitter with three hash tags - "pgachampion. triplebogies. happiness."

"It feels unbelievable," he said. "It seems like a dream and I'm afraid I'm going to wake up here in the next five minutes and it's not going to be real."

The final major of the year was hard to believe in so many ways.

It was Bradley, a 25-year-old PGA Tour rookie ranked No. 108 in the world, who ended America's longest drought at major championships, which had reached six. Phil Mickelson had been the last American to win a major at the 2010 Masters.

He also became only the third player in at least 100 years to win a major on his first try.

All this after Tiger Woods missed the cut and finished out of the top 100 for the first time in a major, and U.S. Open champion Rory McIlroy - the favorite at the PGA - hit a tree root in the opening round and played the rest of the week with his right wrist heavily taped. He finished 19 shot back, in a share of 64th.

Then came the finish - a rousing rally for Bradley, a sad collapse for Dufner. It brought back memories of Ed Sneed making bogey on the last three holes of the 1979 Masters, and even Arnold Palmer losing a seven-shot lead with nine holes left in the 1966 U.S. Open.

Dufner played that four-hole finish in 3 under for the week - never once making a bogey - until the final round. Now winless in 148 starts, Dufner closed with a 69.

"Everybody has struggled on them," he said of the final four holes. "Unfortunately, I had the lead and I struggled on them. ... That was the deciding factor, and Keegan made a couple birdies there, and I made a couple bogeys."

Bradley, best known until now as the nephew of LPGA great Pat Bradley, moved to No. 29 in the world. He won earlier this year at the Byron Nelson Championship in a playoff, again after the leader faded on the closing holes.

The win makes it seven straight majors by players who had never before captured a Grand Slam event, the longest streak ever.

Bradley, who became the first major champion to use a long putter, hopes more will follow.

"I don't want to be one of the guys that kind of disappears," Bradley said. "I would love to be up in a category with the best players and be mentioned with Phil Mickelson, one of my idols. I hope I don't disappear. I don't plan to."

Bradley was two shots behind when he arrived at the pivotal stretch of the course. From left of the 15th green, he hit an aggressive chip that rolled into the water, leading to a triple bogey.

Dufner watched it all unfold from the 15th tee, his lead suddenly up to four shots. For the first time all day, he showed a trace of emotion, wincing when he saw the flight of his tee shot take the ball into the water right of the green.

He poured in a 12-foot putt to escape with bogey and his lead was still four shots heading to the 16th.

Then came an unlikely chain of events.

Bradley made an 8-footer for birdie on the hole, while Dufner hit into the right bunker, blasted out to 10 feet and made bogey, his lead dwindling to two shots.

Dufner then arrived on the 17th tee as Bradley rattled in a 35-foot putt, pumping his fists as his caddie raised the flag over his head. Dufner did well to find the middle of the green for what appeared to be a safe two-putt par. But he ran his first putt 10 feet by the hole and three-putted for bogey.

Just like that, they had a share of the lead.

With the pressure as great as it had been all day, both played the 18th the same way - dry. Both had long two-putts for par from one side of the green to the other. They finished at 8-under 272.

Dufner's 5-iron on the opening hole of the playoff - the uphill 16th - came within an inch of hitting the hole and stopped 6 feet away. Bradley answered with a shot into 4 feet and made the birdie, while Dufner missed his putt.

On the 17th, Dufner again three-putted for bogey to give Bradley a two-shot lead going to the 18th. The final drama for Bradley was watching his 6-iron descend toward the green, clearing the lake with not much room to spare. Dufner rolled in a birdie, but by then it was too late to recover from his mistakes.

"I'm so new at this situation, I don't know if I appreciate it as much as I will - soon," Dufner said. "I might look back in 10 or 15 years and be disappointed if I never get another chance."