They would fire and fall back.

It wasn’t a war of munition, where the falling back is part of the strategy. At Oak Hill Country Club on PGA Championship Sunday, a number of challengers made early runs at the lead. The oaken lady seemed determined that a repeat of Jason Dufner’s Friday 63 would not happen this day.

Keegan Bradley reached 6-under for the day at the 13th green, but made two bogies coming in for 66.

“I wanted to beat’s Duf’s course record [of 63] for sure,” Bradley said after the round. “On 14, I didn’t hit that bad of a drive and it hit the tree and kicked it 60 yards right. Could have just as easily kicked it left and been right in front of the green. But that’s how it goes.”

His playing partner, 21-year-old Japanese sensation Hideki Matsuyama, reached 5-under in his round two holes later, but played 1-over the rest of the way to match Bradley’s 66.

The low number for the day was the eight-birdie, three-bogey effort of Scott Piercy, a 65 that elevated him 21 places into a tie for fifth. But Oak Hill wasn’t setup to demand a low round on Sunday from its leaders. The course required patience and confidence from it champion, and Jason Dufner exhibited both.

Click here to see the clubs in Dufner’s bag.

“For me to be competitive on this type of golf course, I felt like I had to have a great week ball-striking and I was able to do it,” Dufner said. “I hit a lot of fairways. If I did miss the fairways, it wasn’t in the thick, thick stuff.”

Dufner, the 2011 runner-up in this tournament to Keegan Bradley, began the day a shot behind Jim Furyk. Furyk was looking for a second major championship — 10 years past his U.S. Open win at Olympia Fields. He was also looking to salve the sting of recent final-round disappointments, most notably at the 2012 U.S. Open at the Olympic Club.

“I watch a lot of sports in person, and just to watch those guys and how they handle adversity, I think you can learn a lot more from them, and then how they can come back and succeed,” Dufner said.

Dufner marched to a lead at the ninth green, making three birdies and six pars to reach 11-under-par. At that juncture, he found himself two shots clear of Furyk, who made one birdie and one bogey on the front to turn in even-par for the day, 9-under for the tournament.

Jason Dufner’s second shot on No. 13.

The two combatants had their chances to go deeper, but neither could convert attainable birdie putts. Both Dufner and Furyk birdied the No. 16 to preserve the two-stroke differential. After Furyk had trouble with the rough on No. 17 and made bogey, Dufner slid a four-foot putt for par by the side, missing a chance to lock up the tournament.

“I sat here and told you that I was going to have a good time today,” Furyk said after the round. “I was going to have fun. I have no regrets. I played my heart out. I played a very, very solid tournament … I was 1-under par with two to play. With the lead it was a good, solid round, but got beat by a guy that played better today.”

When both golfers drove into the right rough on No. 18, the pressure increased. Furyk’s approach missed the green left and he took a second consecutive bogey to finish at 8-under. Dufner played safely in for bogey and became the 2013 PGA Champion, by two strokes over Furyk.

“He [Bradley] always jabbed at me a little bit about having one of these [Wannamaker Trophy] in his house, and thanks for giving it to him and all that stuff,” Dufner said. “And now I’ve got one, too. It’s pretty neat to come back and win a PGA to be honest with you.”

Other golfers took a run at the lead. Australian Jason Day, a common figure on Sunday at major championships, made seven birdies from No. 4 to No. 13 to reach 6-under for the tournament. But the young maverick closed the way he has so many other times, bogeying Nos. 16, 17 and 18 to end his run.

Henrik Stenson, attempting to become the first Swede to win a major golf title, reached 2-under for the day and 9-under for the tournament with a birdie at No. 13. In hindsight, one more birdie over the closing five holes would have brought Stenson to the magic 10-under figure. But as with so many other contestants, the closing quintet of holes brought him two bogeys and a third-place finish, his second consecutive top-three finish in a major event.

“I think I kept it together nicely,” Stenson said. “Made a bit of a charge, made a good birdie on 13, bit unlucky, ended up in a divot just short of the green on 14, ended up making bogey there and that kind of killed the outside chances I had on the back nine to make a charge.”

Fellow Swede Jonas Blixt stood one ahead of Stenson before a bogey-bogey finish reduced his final tally to 6-under and fourth place alone.