Dufnerâs countenance â lips together, shoulders drooped and eyes watchful but impassive â did not change as the ball dodged history.  Nor did he look impressed when he tapped it into the hole moments later to become the 24th player to shoot a round of 63 in a major. He had also taken the lead at the midpoint of the P.G.A. Championship and had set the competitive-round course record at venerable Oak Hill Country Club.  Dufner was aware of the consequence of the moment. He was only being himself. As only he could, he later explained.  âIf I had that last putt over,â he said blankly, âI would have hit it harder.â  Understatement is Dufnerâs most demonstrative method of expression, something he has turned into an Internet sensation that began with Dufner slouched and inert against the wall of a childrenâs classroom. It has made Dufnering a popular verb, with his torpid pose imitated worldwide, and it has won him legions of fans who line the fairways as he plays, slumping against trees in tribute as he passes.  In a community of pro golfers known for their fitness regimens, beaming smiles and spotless clothes, Dufner is the shaggy-haired cousin with a paunch and a brow as wrinkled as his shirt.  It is hard to keep a crease when slouched against a wall.  Asked about his cult hero status Friday, Dufner almost smiled and said: âPeople have kind of latched onto my personality and how I play golf and carry myself. Itâs great to have people identifying with you in whatever wayâ they see fit.  He added, âFor me, itâs neat for people to want to come to the golf course and watch me play golf.â  Dufner, whose two-round total of 131 and nine under par was a P.G.A. Championship record and gave him a two-stroke lead over Adam Scott, Matt Kuchar and Jim Furyk, had five birdies and an eagle. He holed a 105-yard sand wedge from the second fairway for the eagle and steadily made his way up the leader board from there.  His 63 bettered the Oak Hill record of 64 set in 1942 by Ben Hogan and tied by Curtis Strange in 1989. Earlier Friday, Webb Simpson also shot 64.  Dufner was trailed by fans wearing âDufâs Dipsâ T-shirts, a gaggle who chanted â63â at the end of his round, something that did â for a second â draw a wide grin from the object of their attention.  Heavy rain in the morning had soaked the greens and fairways, making the course susceptible to a low round. Players could tee off with their drivers knowing that a slightly wayward shot would not run through the fairway. Aggressive approach shots to greens were less risky, since the ball would check up on the soft putting surfaces.  Holding the lead at the P.G.A. Championship also had some personal symbolism for Dufner. Two years ago, he led the tournament by five strokes with four holes to play. He bogeyed three holes and then lost the title in a playoff with Keegan Bradley.  Dufner has rebounded to become a star on the PGA Tour, and not just for his wall sitting.  âIâve got more experience now in these majors,â Dufner said. âIâve won some events and been close to winning some others. That will help. Iâm looking forward to closing one of these out. Iâm excited to be in the lead.â  He did not look excited. But that is not unusual.  Friday did not dawn as if it would be a record-setting day. A pelting rain threatened to turn Oak Hill into a modern version of the Erie Canal. Players who had gleefully breezed around the golf course a day earlier in the opening round were dour, disheartened and dropping strokes.  âIn the morning, you just kept your head down and hoped to hang on without drowning,â said Scott, a co-leader after the first round who shot 68 to remain in close contention.  After about two soggy hours, the clouds parted, the sun came out and the sprint up the leader board began.  Simpson, who was five over par near the midpoint of his first round, led the charge with a first-nine score of 32. He then had four birdies in his next six holes to go to seven under for the day. But his run at 63 ended with a late bogey, and he finished with a second-round total of four under par, which put him in a tie for ninth place.  Playing three groups behind Simpson was the threesome of Scott, Justin Rose and Phil Mickelson, the winners of the first three majors this year.  Rose shot 29 on his second nine for a four-under-par 66 that put him in a fifth-place tie with Henrik Stenson at six under for the championship.  Mickelson faltered off the tee for a second consecutive day, recording his second straight one-over-par 71.  Tiger Woods, after a 71 in the first round, sprayed shots left and right, an imprecision that led to an even-par 70. He was at one over par and in a tie for 38th.  In the end, it was Dufnerâs day, and his fellow competitors were animated about his chase of 62 â even if he was not.  Kuchar was playing one group behind Dufner. He watched from the 18th fairway as the putt that could have broken a record was being lined up on the green.  Kuchar, who like Dufner is chasing his first major championship, knew that another Dufner birdie would extend his lead.  âBut we were all kind of hoping anyway,â Kuchar said. âIt would have been pretty cool to see a 62 posted in a major championship. Itâs kind of too bad that he missed.â  Kuchar was asked if he observed Dufnerâs reaction.
A birdie putt that was left short on 18 kept Jason Dufner from breaking the record for low round in a major.