PITTSFORD, N.Y. (AP) — Brooks Koepka has his health back, along with his swagger. Now he gets another chance to restore his reputation as golf’s toughest customer in the toughest championships.

Oak Hill was every bit of that on a rainy Saturday in the PGA Championship, and Koepka was up to the task. With three big birdies over the last seven holes, Koepka had a 4-under 66 — the low round at Oak Hill for the second straight day — to build a one-shot lead over Viktor Hovland and Corey Conners.

“I like it when it’s difficult. Today was super difficult,” Koepka said. And then with the slightest grin he added, “I’ll take 4 under.”

Now he has to finish it off, just like he did with such great poise when he won back-to-back in the U.S. Open (2017-18) and then back-to-back in the PGA Championship (2018-19), earning the rank of “Major Brooks.”

This is his second straight 54-hole lead in a major. He was two ahead at the Masters until playing it safe in the final round and closing with a 75 as Jon Rahm tracked him down and beat him by four shots.

“I know what I did,” Koepka said. “I promise I won’t show up like that tomorrow.”

It wasn’t just the Masters.

Koepka was two behind Dustin Johnson going into the final round of the 2020 PGA Championship at Harding Park when he boldly said, “When I’ve been in this position before, I’ve capitalized. He’s only won one. I’m playing good. I don’t know, we’ll see.” And then he shot 74 and tied for 29th.

A year later, he played in the final group with Phil Mickelson at Kiawah Island in the PGA Championship, played the par 5s in 4 over and shot 74 to finish second.

Koepka has looked so strong that he has made only two bogeys the last two rounds, as pivotal as his 10 birdies on an Oak Hill course that’s a brute even in pleasant weather. Only nine players broke par on Saturday. He was more than 6 1/2 strokes better than the average score.

The last player to have the low score in the second and third rounds of a major championship was Tiger Woods in the 1997 Masters, which he won by a record 12 shots.

Koepka, who was at 6-under 204, won’t have it that easy.

Conners played Oak Hill like a U.S. Open — that’s what this PGA Championship feels like — by opening with two birdies and 13 pars that kept him in front for so much of the wet, grueling day. And then one swing changed everything.

He was in a bunker right of the 16th fairway when he hit the ball so thin that it disappeared into the lip of the soggy turf. Conners wasn’t sure where it went, looking up as if it had bounced out toward the fairway.

It was plugged deep in the sod, and Conners had to drop it in gnarly rough on top of a mound framing the bunker. He did well to advance that toward the green into more thick grass and took double bogey.

“Wish I could have that one back,” he said.

Conners, in control for so long, settled himself for two tough pars for a 70.

Hovland overcame mistakes early with three birdies in a five-hole stretch around the turn. But then the Norwegian failed to take advantage of the scoring stretch — Nos. 13, 14 and 15 — and took bogey from the bunker on the 18th hole for a 70.

He will be in the final group of a major for the second time. Hovland was tied with Rory McIlroy in the British Open at St. Andrews last summer and closed with a 74.

Missing from all this activity was Scottie Scheffler, the No. 2 player in the world, who started with two straight bogeys and didn’t make a birdie — his only one of the round — until the 14th hole. He shot a 73, but is still very much in the mix.

“I didn’t shoot myself out of it on a day where the conditions were tough and I didn’t have my best stuff,” Scheffler said. “I hung in there pretty good and didn’t post the number I wanted to, but I’m still only four back going into tomorrow. And if I go out and have a great round, I think I’ll have a decent chance.”

So is Bryson DeChambeau, who played with Koepka and took double bogey on the sixth hole for the second straight day. He ground out a 70 and was three shots behind.

McIlroy was about like the weather — promising and then bleak — during a wild round that ended with a par save for a 69. He was among only seven players under still under par, but still five shots behind the four-time major champion Koepka.

Asked if there was a 65 at Oak Hill, McIlroy said he would have to keep mistakes off his card.

“I have to believe that there is a score like that out there because … I’m going to have to shoot something like that to have a chance to win,” he said.

Oak Hill was already difficult. And then rain began at the start of play. It never really let up except for a brief burst of sunshine and shadows, and then the showers returned. Fairways were framed by umbrellas. The rough was thick and wet. McIlroy was among players who wore their caps backward to keep rain from dripping off the bill.

Koepka motored along, and he was particularly sharp with the putter on the back nine. He holed a 15-foot birdie putt on the 12th and made one from 18 feet on the par-5 13th. The real boost came on the 17th, when he rolled one in from just outside 45 feet.

“Felt like it was a bit more aggressive today,” Koepka said of his putting. “Especially on the back nine, and putts started banging in the back of the hole.”

And then came Conners’ blunder on the 16th, Hovland’s bogey on the 18th, and Koepka was all by himself atop the leaderboard as he chases a fifth major, and a third PGA Championship. Since the PGA switched to stroke play, only Jack Nicklaus (five) and Tiger Woods (four) have won the Wanamaker Trophy at least three times.

“That would be pretty special to be in a category with them,” Koepka said.

Also at stake: A victory moves him to No. 2 in the Ryder Cup standings. Because Koepka plays for LIV Golf, he can only earn Ryder Cup points in the majors.

Justin Rose joined Scheffler at 2-under 208, still very much in range. And no one appears to be having more fun than California club pro Michael Block. He had another round of 70 and tied for eighth, the first club pro to be in the top 10 after 54 holes since 1990 at Shoal Creek.