Webb Simpson shot a 72 on Thursday that felt like a 64.

Then he went out and shot an actual 64.

Simpson, who was at 5 over after his first eight holes of the PGA Championship, surged into contention Friday by tying the course record at Oak Hill. With a 6-under 64 in the morning, he was at 4 under overall, three strokes behind early leader Adam Scott.

Simpson didn't know the course record, but he was almost positive that 63 was the mark for a major. And when he made four birdies in five holes to reach 7 under with three to play, he couldn't help but fantasize about history.

"I made the turn — I'm still trying to make the cut. It's amazing how a day like today, you go from outside the cut line, to just in, to going for the all-time major record," Simpson said. "It's a big swing of emotions. But the mind is powerful, so I was just trying to not think about it and just stay kind of in my rhythm."

The 2012 U.S. Open champion had five bogeys and a double bogey through eight holes in his first round. He gave himself a little pep talk on the seventh green.

"I said, 'If I have any chance in this golf tournament, any chance at all just to contend, I have to be patient the rest of the day,'" he recalled. "I wanted to get mad. Wanted to throw clubs and do all that, but it wasn't going to help anything."

He followed his own advice with four birdies on the back nine, including one on No. 18 to end the day with confidence cresting.

As the rain let up Friday, Simpson made three birdie putts of about 10-12 feet on his back nine. A 35-footer on No. 5 gave him an inkling something special might be happening.

And a conundrum.

"It's so hard because, on one hand, you want to go for it. You want to go for the record," Simpson said. "But you can't do that on a golf course this hard."

He needed to stay patient and conservative.

"This game is so funny — when you try to make birdies, it seems like you don't," he said. "It was there. It's like the elephant in the room."

One of his playing partners, Angel Cabrera, withdrew with a wrist injury after 11 holes, and Simpson said that helped in the wet weather by giving him more time between shots.

He slipped back to 6 under with a bogey on No. 7 after his second shot got tangled in the branches of one of the towering trees lining the hole. The ball came down in rough so deep Simpson had to ask a spectator where it landed.

After just missing birdie putts on his last two holes, Simpson learned he tied the record first set by Ben Hogan in 1942 and matched by Curtis Strange at the 1989 U.S. Open.

"Any time you can put your name near Ben Hogan, it's a great thing," he said. "So it will go down as one of my most special rounds ever."