Jason Dufner played the round of his life, becoming the 24th player to shoot 63 in a major championship and taking the top spot at the PGA Championship.
Dufner shot five birdies, a hole-out eagle on No. 2 and never made a single bogey, moving to 9 under and breaking the course record previously set by Ben Hogan in 1942, matched by Curtis Strange in 1989, and equaled by Webb Simpson earlier on Friday.
"To join history, to shoot 63 in a major, pretty unbelievable," said Dufner. "And to be leading the tournament, even better. So hopefully, it will propel me to a great weekend."
Dufner, who lost in a playoff to Keegan Bradley in the 2011 PGA Championship, is in search of his first career major victory.
"I obviously had a fantastic day today in a major championship, chased a little bit of history," said Dufner, who left his shirt, his cap and the glove he was wearing, which the Professional Golfers of Association (PGA) shipped to their Florida museum. "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."
Top player in the world, Tiger Woods, had a frustrating second round at the PGA Championship, 36 holes behind Dufner and looking to make up ground. Woods only hit seven of 14 fairways and 13 greens Friday, and finished the day bogeying on 18th hole and is 1 over par for the tournament, currently tied for 39th overall on the leaderboard.
"Just the way it goes," said Woods after his second round. "Obviously, I need to hit it better than I have, obviously keep the ball below the hole so I can be aggressive with the putts.''