Jason Dufner celebrates after a birdie on the 11th hole during the second round of the PGA Championship golf tournament at Oak Hill Country Club, Friday, Aug. 9, 2013, in Pittsford, N.Y. (AP Photo/Charlie Neibergall)
AT A GLANCE
When : Today-Sunday.
Site: Oak Hill Country Club, Pittsford, N.Y.
Leading: Jason Dufner, who shot a 7-under 63 and is at 9 under.
Pursuing: First-round co-leaders Adam Scott and Jim Furyk, and Matt Kuchar are two shots back.
Tiger watch: Tiger Woods shot even-par 70 and lost ground. He’s 10 strokes behind Dufner.
Key statistic: The cut was at 143, lowest at a PGA Championship since 2001 at Atlanta Athletic Club.
Noteable: Twenty-five players have carded rounds of 63 in a major championship. Only five have gone on to win the tournament.
TV: Saturday and Sunday, 10 a.m. to 1 p.m., TNT; 1 p.m. to 6 p.m., Ch. 2.
Full scores, Saturday tee times, Page 33.
Updated: September 11, 2013 6:12AM
PITTSFORD, N.Y. — When Webb Simpson shot a 64 on Friday morning, he tied the Oak Hill course record, which had stood for nearly a quarter-century.
The 2012 U.S. Open champion was able to enjoy the moment for only a quarter of a day.
Jason Dufner fired a 63 in the afternoon, becoming the 24th golfer to tie the record for the lowest round shot in a major. That 7-under par performance gave the low-keyed former Auburn star a two-shot lead at the halfway mark of the PGA Championship.
‘‘It was a good day to get out there and score,’’ Dufner said. ‘‘Obviously the rain, the soft golf course made it scoreable. To make history, to shoot 63 in a major, is pretty unbelievable. To be leading the tournament is even better.’’
Dufner, who stands at 9 under, is being chased by Adam Scott, Matt Kuchar and Jim Furyk, who are tied at 7 under.
Dufner’s 63, which was highlighted by an eagle on the second hole, a 401-yard par 4, eclipsed the 64 first shot by Ben Hogan here in 1942. It was matched by Curtis Strange at the 1989 U.S. Open and Simpson’s morning round.
‘‘In my head, I was just trying to get further and further away from the field, trying to make birdies,’’ said Dufner, who tuned out some raucous gallery encouragement. ‘‘It’s great to be part of history. But it would be even greater to close this championship off.’’
Brace yourself for a wild weekend. With Tiger Woods coming off a seven-stroke victory last week and Phil Mickelson trying to build on a rousing win at the British Open last month, the focus was on the world’s top two players heading into the PGA.
Heading into the weekend, though, it looks like just about anyone but Tiger or Phil can win.
Prominent on that list are Masters winner Scott and U.S. Open champion Justin Rose (6 under), who are trying to notch their second major titles of the season.
Meanwhile, Woods (71-70, 1 over par) and Mickelson (71-71, 2 over) limp into the weekend needing miracle finishes to hoist the Wanamaker Trophy on Sunday.
Woods is tied for 39th, and Mickelson is tied for 50th. That’s a lot of players, as well as a lot of strokes, to overcome.
If Scott or Rose win, they’ll be reversing a recent trend. The last 20 majors have been won by 18 different players. Mickelson and Rory McIlroy are the only repeaters since Padraig Harrington won the British Open and the PGA in 2008.
‘‘I was hungry before the Masters, and I might even have a bigger appetite after it,’’ Scott said. ‘‘It might be greedy, but I feel like this is my time to get everything I want out of my career, and I’m going to keep pushing until I do. My game is in great shape. I’ve got to take advantage of it. Otherwise, it’s all a waste.’’