FARMINGDALE, N.Y. — Brooks Koepka is turning a public golf course into his private playground in the PGA Championship.
Staked to a seven-shot lead, Koepka never let anyone get closer than five shots Saturday as he powered his way to an ideal start and overcame a few sloppy mistakes for an even-par 70.
For the first time this week, he didn’t touch any scoring records. That wasn’t the objective.
Koepka kept his seven-shot lead going into a final round that feels more like a victory lap as he tries to join Tiger Woods as the only players to win back-to-back in stroke play at the PGA Championship.
Asked if there was any doubt he would win, Koepka said flatly, ‘‘No.’’
‘‘I feel confident. I feel good. I feel excited,’’ he said, and only the last part was hard to believe because Koepka doesn’t show much excitement about anything. He picks a shot and hits it, and over three days at Bethpage Black, the ball is going exactly how he wants.
No one has gone wire-to-wire in the PGA Championship since Hal Sutton, who had a two-shot lead going into the final round at Riviera in 1983.
Koepka has the largest 54-hole lead in the PGA Championship since it switched to stroke play in 1958, and no one has lost a seven-shot lead in 159 years of major championship golf. In fact, no one has lost more than a six-shot lead in any PGA Tour event.
Dustin Johnson tried to make a run with six birdies, only to stall with five bogeys in his round of 69. No bogey was more damaging than the 18th. A drive into the fairway would have given the world’s No. 1 player a reasonable shot at birdie. Instead, he sent it right into the bunker, came up well short into the native grass, left the next one in the bunker, and had to scramble to limit the damage.
That kept Johnson from joining his close friend in the final group.
Koepka, who was at 12-under 198, will play the final round with Harold Varner III, whose week began with plans to play a practice round with Woods on the eve of the PGA Championship until Woods called in sick.
Varner birdied the 18th to cap a bogey-free 67 and lead the group at 5-under 205 that includes Jazz Janewattananond (67) and Luke List, who holed two shots from off the green for a 69.
‘‘I think we’re all playing for second,’’ List said.
Jordan Spieth did not put any pressure on Koepka at all. Playing in the final group on the weekend for the first time since the British Open last summer, Spieth didn’t have a realistic birdie chance until the sixth hole, and he missed that one from 8 feet. He shot 72 and was nine shots behind.
Spieth would not speak to a reporter after the round.
There was simply no stopping Koepka, who is one round away from a fourth major in his last eight tries and a return to No. 1 in the world. Koepka also would become the first player to hold multiple back-to-back major titles at the same time. He won his second straight US Open last year 60 miles down the road at Shinnecock Hills.
Woods and Phil Mickelson are the only players in the last 30 years to win at least one major three years in a row.
That’s the kind of company Koepka is on the verge of joining.
The plan for Sunday was no different from the previous three rounds.
‘‘It doesn’t really matter. I’m just trying to play good golf,’’ Koepka said. ‘‘If I can get off to a good start tomorrow, these first six holes are very scorable. I feel like if you can get 1 or 2 under after six, you’re in a good spot.’’
That’s what worked on Saturday.
Koepka had birdie chances on the opening six holes and converted two of them, from 5 feet on a blind shot up the hill at No. 2, and a gap wedge that landed next to the pin and settled just over 2 feet away on No. 5.
His only struggle was missing a 2-foot par putt on the ninth hole for a three-putt bogey, and then missing the 10th fairway to the right to set up another bogey.
The most important putt for Koepka was just under 5 feet for par on the 11th, which kept him from three straight bogeys.
And then he was back in his groove.
List ran off three straight birdies, chipping in from 70 feet on No. 12, holing a 30-foot putt on the par-5 13th, and making a 15-foot putt on the 14th. That pulled him within five, but it wasn’t long before Koepka birdied the 13th and List began missing enough shots that it finally cost him.
‘‘I’ve got a lot to play for,’’ List said. ‘‘If I start worrying about what he’s doing, I’ve got no chance. For me it’s just trying to get through and give myself as many opportunities to get on the green as possible.’’
Johnson has the most experience and skill among those chasing Koepka, if he even allows there to be a chase.
‘‘It’s going to take something special to catch Brooks, but it’s doable,’’ Johnson said. He then tried to work out the math, figuring a low score by Johnson and Koepka going a few shots over par, and then he decided to stick to a more practical outlook.
‘‘I’m going to need some help from him,’’ Johnson said. ‘‘And then I’m going to have to play very, very well.’’