The Brooks Koepka on display Sunday at the Tour Championship wasn’t the same guy most golf fans expect to see in the final round of a big tournament.

Holding a one-shot lead with 18 holes remaining — and paired in the final group with Rory McIlroy, one of his two closest competitors — the four-time major champion and likely PGA Tour Player of the Year failed to flex his muscle all day. On a cool August day that had go-low potential written all over it, Koepka barely got out of third gear.

“Just one of those days where you don’t feel comfortable,” he said. “I mean, I can’t bring it every day.”

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Koepka shot a disappointing 2 over 72 — he had opened the tournament with a pair of 67s and a 68 — and wound up tied for third, five shots behind McIlroy.

Koepka was still hitting it a mile — he averaged 323 yards on Sunday and 321.1 yards for the tournament — but the accuracy wasn’t there. He hit only five fairways in the final round, forcing him to play from East Lake’s dense Bermuda rough — or worse.

“Just didn’t put the ball in play, man,” Koepka said. “If you’re not going to put it in play, you’re going to have a hard time scoring, you’re going to have a hard time controlling your distances.”

The decisive body blow for Koepka came at the seventh hole when he hooked his tee shot into the trees. After sending out a search-and-rescue team to poke around every pine cone in the vicinity, the ball was declared lost and Koepka had to play his 357-yard provisional drive. He wound up taking a double-bogey.

That misfortune, coupled with McIlroy’s birdie, flipped the scoreboard. Suddenly, Koepka’s one-shot lead had turned into a two-shot deficit. It was a three-shot swing from which he never recovered.

Koepka got a temporary reprieve when he birdied the eighth hole, but lost any shot to catch McIlroy with three consecutive bogeys at No. 12, 13 and 14.

“Those three putts I missed kind of right there in a row, 12, 13, 14, kind of took the air out of everything,” he said.

Koepka said earlier Sunday that he'd fallen into some "old bad habits" the last few weeks. His playoff finishes weren't great — a tie for 30th at the Northern Trust and a tie for 24th at the BMW Championship. But between the end of the third round, which was completed on Sunday morning, and the start of the final round, Koepka was at ease with his game.

After taking a nap and grabbing a bite of lunch, Koepka headed for the range for his final warmup. That’s when he discovered something just wasn’t right

“It was one of those days where even on the range, I didn’t feel very comfortable with the driver,” he said. “I just couldn’t — it wasn’t fading enough. Everything was kind of left and it happens once in a while.”

The result was a rare stumble for Koepka, who won three times this season — including the PGA Championship — and nearly claimed his third straight U.S. Open title.

“This year was very, very consistent,” he said. “This week just didn’t get it done. I don’t think I was going to beat Rory today, even if I had it. But pleased with the season overall.”

Afterward, Koepka took a deep breath and talked about his plans for the next five weeks, an itinerary that includes no golf and plenty of off time, perhaps on a beach.

“Vacations,” he said. “I’m going to enjoy myself.”