FARMINGDALE, N.Y. – Brooks Koepka’s stoic demeanor has become as much a part of his persona as his powerful drives, But late on Sunday at the PGA Championship, as his lead was slashed to a single stroke, that calm resilience was tested.

“I wasn't nervous. I was just in shock, I think. I was in shock of what was kind of going on,” said Koepka, who won his fourth major title and second PGA.

What was going on was a borderline collapse from Koepka, who saw a seven-shot lead slipping away as he bogeyed Nos. 11, 12, 13 and 14.

“I can't tell you the last time I made four bogeys in a row,” Koepka said.

His anxiety likely reached its peak on the par-3 14^th hole, when his tee shot sailed through the wind and over the green. As Koepka prepared to hit a delicate pitch, Dustin Johnson, playing in the group ahead, birdied the 15^th hole to cut Koepka's advantage to just one.

Although he stopped short of calling it nervousness, Koepka’s caddie Ricky Elliott said it was the first time he’s seen his boss anxious on the golf course.

“I just got the feeling we were dropping so many shots. Anybody would get nervous,” Elliott said. “When [Johnson] birdied 15, we heard the roar and we were making a mess of 14. We just talked going down the hill, 'Listen we’re still there, we’re still in the lead, he’s got tough holes to play. You’ve bogeyed four in a row so there’s a good chance you’re going to par a few.'”

Koepka stopped the slide with pars at Nos. 15 and 16 and scrambled for a par at the last hole for a two-stroke victory.