Berger's lead narrows at rain-hit Arnold Palmer

Berger -- a four-time PGA Tour winner, chasing his first title in five years -- led by six strokes before the break. When play resumed, the American runaway leader survived a scare on 13 as his ball somehow held up in thick grass on the water's cusp.

But he still had to settle for a bogey after two-putting, and completed just 15 holes before darkness fell, allowing the chasing pack to gain ground.

His playing partner Akshay Bhatia sank a twilight birdie on the 16th, while Berger opted not to attempt his eagle putt on the same green until Sunday.

"Sixteen was kind of a must... It's fun to be in the hunt," said Bhatia.

Two shots further back was Sepp Straka who carded 66, the day's best score. The Austrian shared third place with Collin Morikawa and Cameron Young, who made a fine 67 featuring four straight birdies at the turn.

Morikawa said barely managing to finish his third round could be an advantage, with the leaders forced to tee off early again Sunday to complete theirs.

"Just being able to wake up and sleep in, and just kind of get the day situated, it's a huge kind of momentum thing I think for the routine," he said.

- 'Beats you up' -

McIlroy withdrew before the third round began, citing a lower back problem.

The world number two said in a statement he had felt a "small twinge" in his back while warming up in the gym.

"As I started hitting balls on the range before the round, it worsened and developed into muscle spasms in my lower back," the Northern Ireland star said. "Unfortunately, I'm not able to continue and have to withdraw."

McIlroy's withdrawal comes at a critical period of the season, with the five-time major-winner due to defend his Players Championship title at TPC Sawgrass and his Masters title at Augusta next month.

Elsewhere, Scheffler endured another rollercoaster round, a day after tossing his ball into the 18th hole's lake in frustration.

Scheffler started Saturday with a string of bogeys, made four straight birdies on the back nine, then ended with a double bogey.

He found the water with an aggressive line from very deep rough on the final hole, then wedged the ball into a bunker.

"When you hit it in the rough out here you don't know what you're going to get," said Scheffler.

"Sometimes you can get the ball on the green. And then you look at the lie I had on one, I can't hit it more than 90 yards, and I'm not necessarily weak in terms of speed."

The end result was an eventful 72 that left Scheffler where he began, on three under.

"Pretty up and down, I would say," Scheffler summarized, joking that "golf's a game that kind of beats you up."

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