Brooks Koepka passes Bethpage Black test with flying colours

It is a fearsome course set up to test the mental strength, shot-making and physical fibre of anyone who steps on to the 7,459-yard layout, which this week put an even greater premium on distance given rain-softened conditions.

Defending champion Koepka, who has won three majors in the last two years, passed the test with flying colours as he tied the course record with a seven-under-par 63 that many had considered improbable when the day began.

"You can't miss -- you can't take a shot off, and that's what I love. It reminds me -- I think that's why I play so well at U.S. Opens, this golf course, typical U.S. Open golf course," Koepka told reporters.

"I mean, if you don't have a good day, you can very easily shoot five, six-over. There's a fine line between five, six-over and a couple under out here.

"It's a fun golf course to play, that's for sure."

Of all the adjectives thrown around to describe Bethpage Black in the lead-up to the year's second major, fun was not a word that anyone had the gall to utter.

But Koepka, who has used a mix of sheer athleticism, raw power and quiet confidence to dominate the sport in recent years, did seem to enjoy his bogey-free trip around a course that got the better of many big-name players.

Koepka wasted little time getting to work as he drained a 40-foot birdie putt at his opening hole, the par-four 10th. He grabbed the outright lead with a birdie at the par-four first and pulled away with birdies at the third, fifth and ninth holes, the latter where he drained a 33-foot putt.

"That was one of the best rounds I've played probably as a professional," said Koepka, whose 63 equalled the second-lowest round in any men's major championship.

"This golf course is brutal. If you're not going to drive it, like I said, it tests every asset of your game," said Koepka.

"You've got to drive the ball straight. It's long, so you've got to hit it far and really position yourself with some of these shots in."

Koepka said his mind and game are in a great spot, which does not bode well for anyone hoping to deny him from adding a second PGA Championship title to a major haul that also includes two U.S. Open wins.

"It's never been this confident," Koepka said. "I think I'm still learning, understanding my game, and I've figured it out, and I think over the next few years, I'm excited for what's to come."