Wilfredo Lee / AP

Phil Mickelson reacts after missing a chip for eagle on the 16th hole during the third round of The Players Championship on Saturday. Mickelson shot a 6-under 66.

By Doug Ferguson

updated 8:51 p.m. ET May 8, 2010

PONTE VEDRA BEACH, Fla. - One round away from one of the biggest wins of his career, Lee Westwood of England knows what to expect on the final day of The Players Championship.

Not only because of his 16 years and his 30 victories worldwide, or his 54-hole lead last month at the Masters.

Saturday on the TPC Sawgrass was enough of a reminder.

Westwood watched a two-shot lead turn into a two-shot deficit. Over the final hour, Robert Allenby picked up three shots on the last three holes, while Heath Slocum dropped four shots on the last six holes.

The day ended with Westwood hitting a daring shot with a 6-iron through a gap in the trees for a par on the 18th hole for a 2-under 70 to finish the third round with a one-shot lead, same as he started. He has more company now — Masters champion Phil Mickelson included — but the course is as significant as the names behind him on the leaderboard.

"There was no real scope for thinking about anything else other than what I was doing," Westwood said. "It's that kind of golf course. If you play well, birdies are available. If you don't hit good shots, they penalize you. That's what good golf courses do to you."

This day, there was a little of both.

Mickelson suddenly was back in the picture, along with that No. 1 ranking, because of his 66 that put him five shots behind.

Tiger Woods was not, courtesy of a bogey-bogey finish for a 71 that put him 10 shots behind.

Allenby was five shots behind when he walked off the 13th tee. He made up ground quickly with a 6-iron to about 12 feet on the par-5 16th for eagle, then a 12-foot birdie on the island-green 17th that curled into the side of the cup. He shot a 67 to get in the final group.

"That's the thing," Allenby said. "You don't know what's going to happen out there. All you can do is just play your own golf. But I knew I had to push it a little bit just to try to get within reach. Obviously, the leaderboard changed a couple of times through the back nine. Luckily for me, I did well on the finishing holes."

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Westwood was at 14-under 202.

"The golf course changed a lot. It got really firm this afternoon," Westwood said. "I thought I played well — gave myself a lot of chances, missed a couple, but all in all, I was pleased with the way I played. I didn't make too many poor shots out there."

He certainly didn't on the 18th after his drive landed in a drain grate. He took a free drop, saw a gap in the trees and hit a 6-iron onto the green to give himself another shot at winning.

"Had to go under one limb and then over the next lot of trees," Westwood said. "It just looked perfect for the trajectory."

Mickelson began the day nine shots out of the lead, same as Woods.

They went opposite directions, however. Mickelson didn't make a bogey until the final hole for a 66 to put himself back into the picture, just five shots behind Westwood. The 10 players ahead of him have a combined 14 victories on the PGA Tour.

"I feel like things started to click a little bit today, and I think I've got one more low round in me," Mickelson said. "I just hope that it will be enough, that I'll be within striking distance."