Three majors in two years, and Brooks Koepka can still feel as though he has something to prove.

He delivered again on golf's biggest stage.

And this time, Tiger Woods was along for the ride.

Koepka beat up on brawny Bethpage Black for a record-setting start to his title defense in the PGA Championship. With a 40-foot birdie to start his round and a birdie putt from just inside 35 feet at the end, he shot a 7-under 63 to break the course record and become the first player to shoot 63 in the same major twice.

"That was one of the best rounds I've played probably as a professional," Koepka said. "This golf course is brutal."

He was 10 shots better than the average score in the opening round, but only one better than Danny Lee on a day when only 16 players broke par, the fewest for the first round of the PGA Championship since 2008 at Oakland Hills.

It was only one round, but enough to make the Masters that Woods won last month feel more nostalgic than a sign of more to come.

"I felt like I won this last year. I'm playing good," Koepka said. "It was great that Tiger won Augusta, but I mean, we're at a new week now. ... Obviously, everyone is going to be cheering for him, and it's going to be loud, especially if he makes a putt. You've just got to keep battling."

Thousands of fans who trudged across muddied paths to the far end of Bethpage Black on Thursday morning were drawn to Woods, a Masters champion again, announced on the 10th tee as the PGA champion from 1999, 2000, 2006 and 2007.

The introduction took long enough to remind everyone what Woods has done in the game.

Koepka then showed what he has done lately — back-to-back U.S. Open titles, a PGA Championship and an ideal start in his bid to join Woods as the only back-to-back winners of the PGA Championship in stroke play.

"I wasn't surprised," Lee said. "I mean, have you seen him playing U.S. Opens and PGA Championships in the last three years?"

Woods looked rusty early, inspired in the middle and sloppy late in his first competition since his emotionally draining victory at the Masters.

He opened with a pair of double bogeys on the back nine and ruined a torrid start to the front nine — two birdies and a 30-foot eagle in a four-hole stretch — with a pair of three-putt bogeys. That gave him a 72, leaving him nine shots behind and ending 12 consecutive rounds at par or better in the majors dating to the U.S. Open last summer.

"It wasn't as clean as I'd like to have it, for sure," Woods said.

Tommy Fleetwood had a 67, while the group at 68 included Pat Perez, who played a practice round with Koepka on Tuesday. Jordan Spieth overcame a double bogey on the 10th hole for a 69 and was in a group that included Dustin Johnson, Phil Mickelson, Rickie Fowler and Jason Day.

"The course is not easy, but Brooks obviously made it look real easy," Perez said. "I saw that on Tuesday when I played with him. I actually congratulated him on his win."

But it's far from over, even before Lee made his afternoon move to cut into the lead. Fowler was bemused when asked how close he would have to be to Koepka heading into the final round Sunday.

"What makes you think he's going to be leading?" Fowler said. "I would say there's no lead really safe here."

Koepka failed to birdie the two par 5s, missing a 10-foot birdie putt on No. 13 and scrambling for par on the easier fourth hole. He also missed a 7-foot birdie putt on the 11th and an 8-foot birdie putt on No. 2. Yes, this could have been special. Then again, he also made four birdie putts of 15 feet or longer, including the long ones at the start and end of his round.

"When that putt went in on No. 10, that was kind of the momentum that set me," Koepka said. "But I never once thought about the course record or anything. I was just trying to shoot the best I could. Simple as that. Just keep going and total them up at the end."

He is the ninth player to open a major with 63, and only two of them went on to win — Jack Nicklaus at Baltusrol in the 1980 U.S. Open and Raymond Floyd at Southern Hills in the 1982 PGA Championship.

There is a long way to go. Considering Koepka's record in the majors — three wins and a runner-up in his last seven majors — this felt shorter. Koepka came seriously close to a bogey only one time, and he made a 10-foot par on the sixth hole.

Woods managed to get under par, but only briefly.

His opening tee shot took enough bounces to barely get into the rough, and it left him no option but to hack out. The mistake was a wedge that went over the back of the green, and Woods threw his head back knowing his mistake. His fast pitch went 6 feet by and he missed to open with a double bogey. His other double bogey came on the par-3 17th when he went into the face of a bunker, blasted out longer and took three to get down from there.

A birdie-birdie start to the front nine, and a 30-foot eagle putt on the par-5 fourth, brought him to 1 under. And then he bogeyed three of the next four holes.

"I fought my way back around there, and unfortunately, I just didn't keep it together at the end," he said.