Jason Dufner has refused to get carried away following his 63 in the second round of the US PGA Championship at Oak Hill.
The American admitted to feeling the pressure in trying to break the course record, but tops the leaderboard on nine-under-par heading into the third round.
"I obviously had a fantastic day today in a Major championship, chased a little bit of history," Dufner told reporters. "Came up a little short on that last putt, but all-in-all I'm excited.
"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-wracking for a Friday. It's usually the pressure you might feel towards the end of the tournament but I got through it. I made a couple of pars, and I wish I had that putt on the last hole back again."
Adam Scott, Matt Kuchar and Jim Furyk are second on seven-under-par.
