With all the tinkering and tweaking of the design and set-up that has gone on at Oak Hill Country Club, all in the name of protecting the par of 70 from being plundered at this 95th PGA Championship, the PGA of America hierarchy must be shaking their heads in disbelief.

On the eve of this championship a revolving door of professionals through the media centre talked up the difficulty of the course; how the rough would force players to chip out sideways; how the narrow landing areas played into the hands of only the straightest of hitters; how the speedy greens would rattle the nerves of the world’s best.

Then came the rain, which extinguished any fire there was in the greens and fairways and allowed the field to take dead aim at the flags.

And, after that, there was the perfect storm going by the name of Jason Dufner, who ripped the heart out of the Oak Hill course with five birdies, a hole-out eagle and no bogies in his round of 63.

At the final hole, he had a chance to shoot the lowest 18-hole score in major championship history but his birdie putt from 12 feet for a 62 rolled to a halt less than a foot from the cup. Instead, Dufner will have to be content with becoming the 24th player to shoot 63 in a major championship.

Jason Dufner taps in for his par at the 18th hole having narrowly missed his birdie which would have given him 62 and an all-time majors championship scoring record. PHOTO: GETTY IMAGES

Of course he did also claim the Oak Hill course record en route to taking the halfway lead in this championship. His flawless round of 63 moved Dufner to nine under – two strokes clear of Masters champion Adam Scott and fellow Americans Jim Furyk and Matt Kuchar – and surpassed the 64 mark set by Ben Hogan (1942), Curtis Strange (1989) and Webb Simpson earlier in the second round. He also claimed the record for the lowest 36-hole score in PGA Championship history.

"I obviously had a fantastic day today in a major championship, chased a little bit of history," said Dufner, who lost to Keegan Bradley in a play-off at the 2011 PGA Championship and remains without a major championship title.

"Came up a little short on that last putt, but all in all I'm excited. The position I'm in, the golf course has obviously yielded some low scores, and I'm looking forward to continuing good play here on the weekend.

" … It's tough when you're chasing history. You will be the first one to do something. I don't think I've been the first to do anything in my life. So it was a little nerve-racking for a Friday. It's usually the pressure you might fell towards the end of the tournament.

"But I got through it."

Dufner couldn’t have asked for a better start to his round, holing a 105-yard approach into the par-4 2nd hole. Dufner hit a pure sand wedge over the top of the pin and into a backstop slope, which helped the ball grab and then spin back about 30 feet and into the hole for eagle.

“I knew I could be aggressive, because you kind of have a backstop there, and with a sand wedge, you know you're going to spin it,” Dufner said. “It probably flew about close to 115 and had almost 30 feet of backspin. So it was a good number, a good fit, hit a good shot and got a little lucky. You can't see it at all.  I had already given the club back to my caddie.  That's how long it took to come back.  When I turned back to the hole, they went nuts, it was a pretty neat experience.”

‘Cyclone Dufner’ made birdies at the 4th and 5th holes and made the turn at four under. More birdies rained down at the 11th, 13th and 16th holes, all of which were converted from inside 12 feet of the hole.

Dufner had plenty of support from the New York golf fans. PHOTO: GETTY IMAGES

The usually laid back Dufner spoke of his pride at getting the course record which had been held by his idol Ben Hogan.

“I've been a great follower of Mr. Hogan and everything that he's done,” Dufner said. “We played at Merion this year for the first time; I was so excited to be there. Dating back to when he won the US Open there and all the history and the plaque there; and then to come to a great course like Oak Hill where he holds the course record and has played numerous rounds here, had great relationships with the Harmons; and to knock his course record off is kind of a tip of my cap to him, and it will be definitely something that I can always look back on when I'm finished playing that I accomplished.”

Hot on Dufner’s heels is Adam Scott, who earlier in the day had to endure heavy rain at times as he consolidated his opening round of 65 with a hard fought 68 containing five birdies and three bogies.

“It was raining pretty hard on and off, and the course was playing tough,” Scott said. “So it was nice to get off to a good start while the tough conditions were out there and I managed to hang on.

“The course is obviously softening up, and I'm sure some guys will take advantage of that. But so far so good for two days.”

Scott will tee off in the last group alongside Dufner for third round. While he no longer has the lead, the Queenslander likes where he stands so far in this tournament.

“I've been working really hard to try and get myself in these kind of positions,” Scott said. “Only halfway there this week, but it's so important to get off to good starts.

“These are such long, tough weeks that if you can get ahead of the game a little bit, it takes a little bit of the pressure off.  But tomorrow is going to be fun.  Hopefully that leaves me in a spot where a good round will give me a chance at the trophy.”

Adam Scott was out in the rainy conditions early and still posted a good score. He's right in the mix heading into the weekend. PHOTO: GETTY IMAGES

A win at Oak Hill would give Scott his second major victory of the season. No one has won back-to-back majors since Padraig Harrington claimed the Open Championship and PGA Championship in 2008.

“I’ve told you that these are going to be my best years and generally they are for any golfer,” Scott said. “I’m doing everything I can to make sure they are. I can’t take my foot off the gas just because I achieved something great at Augusta.”

Scott, who led the Open Championship through 63 holes last month, has finished among the top-10 in six of his last 11 majors. A second major championship would probably be enough to overcome almost anyone else’s season – even Tiger Woods’ five wins thus far

“All it says is that I’m hungry at the moment,” Scott said. “I was hungry before the Masters and I might even have a bigger appetite after it. 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.”

If not for two bogies in his final three holes, Victoria’s Marcus Fraser would be heading into the third round just one shot behind Scott and three back of Dufner. But those late stumbles, see Fraser, still in the top-10 at four under, playing alongside Charley Hoffman in the sixth last group out on day three.

Fraser has been struggling with his putting for a few months but his stroke has returned at Oak Hill, converting nine birdies and a number of long par saves during the first 36 holes.

Queensland’s Jason Day also looked like he was ready to go low in the second round after making birdies at his first and third holes. Teeing off the 10th, Day raced to a share of the lead but he couldn’t make any more birdies in his round. A bogey on the 18th (his 9th hole) and a double bogey on the par-5 4th left him at one over for the round and still not out of contention at two under for the championship.

“The 4th hole … I made a mess there,” Day said. “Overall, I actually played pretty decent again today, just a couple of holes.”

Day said his driving was letting him down and he was planning to use his old driver for the remaining two rounds.

“You know what, I think I'm going to go back to my old driver,” he said. “Just putting it in, I hit the Slider (TaylorMade SLDR driver) great on the range and in the practice round I hit it great, but right now I'm just not hitting it as well as I should.  I think I'm compensating in my other swings with my irons, as well.

“So I think the next step is just to go and hit some balls on the range with my old driver and try to get that feeling back again.”

Although he sits back in a tie for 15th, Day said he was still in a good position to make a run at his first major title.

“I just got to keep chipping away,” he said. “I have got two days to capitalize and try and win my first major.  I think I just got to keep plugging away and playing.

“We're going to get good weather over the next two days and I think the course set-up will be a bit tougher. With the pressure of trying to win a major, it's obviously difficult for us. Hopefully the lead doesn't get away too far.”

Pre-tournament favourite Tiger Woods had an even par 70 and remains at one over for the championship in a tie for 38th and ten shots behind Dufner. He will play with 2011 PGA champion Keegan Bradley in the third round and with fine weather forecast for the weekend he has an opportunity to creep up on the leaders while some softness remains in the course.

“Obviously I’m going to have to put together a really good weekend,” Woods said. “This golf course is pretty soft. It’s definitely gettable. Got to hit the ball in play and keep the ball near the hole so I can be aggressive with my putts.”

Woods never found the right pace on the greens Friday. He left two birdie putts on the edge of the cup and wound up needing 32 putts to complete his round, which ranked 126th in the field.  He even had a pair of three-putt greens, including the par-4 14th where he drove the green and raced his eagle attempt four feet by the hole.

“I made my share and missed my share,” Woods said. “Just the way it goes.”

“I didn’t hit it anywhere near as good as I did yesterday. Consequently I didn’t have that many looks. When I did, I missed my share.”

Woods isn’t flying the white flag just yet.

“I’m going to have to do my job and shoot a good round,” he said. “But then again, I’m so far back that if the leaders go ahead and run off with it and shoot a low one tomorrow, I’m going to be pretty far behind. I have got to post something in the mid-to-low 60s, like some of the guys did today. It definitely can be done.”

SECOND ROUND LEADERBOARD

1. Jason Dufner (US)          68-63–131

T2. Jim Furyk (US)             65-68–133

T2. Matt Kuchar (US)         67-66–133

T2. Adam Scott (Qld)    65-68–133

T5. Justin Rose (Eng)          68-66–134

T5. Henrik Stenson (Swe)   68-66–  134

T7. Steve Stricker (US)         68-67–135

T7. Robert Garrigus (US)     67-68–135

T9. Charley Hoffman (US)   69-67–136

T9. Marcus Fraser (Vic)       67-69–136

T9. Martin Kaymer (Ger)    68-68–136

T9. Webb Simpson (US)        72-64–136

ALSO:

T15. Jason Day (Qld)   67-71–138

T28. Marc Leishman (Vic)    70-70–140

T50. John Senden (Qld)     72-70–142

T60. Matt Jones (NSW)  72-71–143

MISSED CUT (144 and higher)

Brett Rumford 70-77–147; Geoff Ogilvy 74-74–148.