PONTE VEDRA BEACH, Fla. - Jason Day saw The Players Championship at its easiest and toughest, all in the span of nine hours Saturday on what felt like two golf courses.

He set a record when it felt like a shootout.

He was even stronger when the TPC Sawgrass turned into a battle for survival.

And when a long, wild and utterly exhausting day was finally over, the world's No. 1 player could take solace that he still had a four-shot lead.

"I want to say this was the toughest day I've ever had to play in my life," Day said after gutting out a 1-over 73 going into the final round. "I want to win this tournament so bad. I really do. ... But right now, I'm just trying to focus on trying to play well tomorrow. I mean, that's all you could do is just try to survive."

The difference between morning and afternoon was more like night and day.

Day finished his storm-delayed second round with a 66 to set the 36-hole record at 15-under 199, and it appeared he would take aim at more records. And then it all changed. The PGA Tour rolled the greens one more time. The wind picked up. The air dried out. The sun baked out the course.

Suddenly, the greens were like putting on glass.

Day four-putted from 18 feet for a double bogey. He made another double bogey two holes later. But right when it looked like he would fall victim to the fierce conditions, the 28-year-old Australian played the final 10 holes with three birdies and seven pars to reach 14-under 202 and keep his big lead.

More than excited about a chance to win the PGA Tour's premier event, he is worried about facing similar conditions Sunday.

"That would just ruin everything," he said. "That won't make it fun for ... we were out there for nearly six hours today trying to play 18 holes. They made the course pretty much nearly unplayable. If they do make it like that, then I'm just going to have to grind my hardest to win the tournament, and I'm OK with that.

"I won't stop until it's done, and I can rest after that."

It wasn't unplayable for everyone.

Ken Duke in the round of a lifetime made six birdies over his last seven holes for a 65, which was more than 10 shots better than the average score. He was tied for second with Hideki Matsuyama, who made seven birdies in his round of 67. Joining them at 10-under 206 was Alex Cejka, who shot a 72 that felt much lower.

Canadians Adam Hadwin, of Abbotsford, B.C., and David Hearn, of Brantford, Ont., are 2 under and tied for 34th. Hadwin shot a 74 in his third round while Hearn had a 72.

"I don't know what they did to the golf course overnight, but it was playing like a U.S. Open," Cejka said. "It was just lightning-fast greens."

Sixth of the 76 players who made the cut had a double bogey or worse.

There were 149 three-putts — or worse — in the third round. Sergio Garcia took six putts from just off the sixth green. Paul Casey took five putts from about 8 feet on the 15th hole. There was rare a lag putt. The putts wouldn't stop rolling.

"A 10-foot putt felt like it was 60 feet away," Day said.

There was still the traditional trouble at the Stadium Course. Russell Knox hit three shots in the water on the island-green 17th and made a 9 that ruined his round (he shot 80) and his chances. Kevin Chappell had to play his second shot with his feet on the planks framing the water on the 18th hole. Having made two eagles, he closed with a double bogey to fall six shots back after a 70 that felt a lot better.

Jordan Spieth, Phil Mickelson and defending champion Rickie Fowler all missed the cut when the storm-delayed second round was completed Saturday morning. Canada's Nick Taylor, of Abbotsford, and Graham DeLaet, of Weyburn, Sask., also missed the cut. If there was a consolation, it was not having to take on Sawgrass and its scariest.

Day had his moments.

His first blunder was a four-putt double bogey on the sixth hole, which started with an 18-foot birdie putt that he nearly made. It could have been worse. His 5-foot putt for double bogey nearly spun out of the cup. He answered with a wedge to 2 feet for birdie, but then had more trouble off the green at the par-3 eighth. This time, he had to make a 6-foot putt for double bogey.

And while his card was clean on the back nine, the biggest break of all came at the 15th. He was short of the green in three, certain to drop at least two shots, when Day chipped in from just over 50 feet for par. Then, he pounded a 3-wood and hit a towering 8-iron to 6 feet on the par-5 16th. He missed the putt and had to settle for birdie, made a 10-foot par putt on the 17th and finished with a solid par.

One more round, and no one is sure what to expect now.

The average score the opening two rounds was 71.02. It was 75.59 on Saturday, helped by 86 scores of double bogey or worse. There were 163 rounds under par the opening two rounds, and only six on Saturday.

"To have two doubles on the front side and then play some nice golf on the back to really kind of keep that distance between me and the rest of the guys was nice," Day said. "But really hoping they slow the greens down tomorrow."