PONTE VEDRA BEACH, Fla. - Moments after Sean O'Hair finished birdie-birdie-birdie today for a 66 that gave him the lead going into tomorrow's final round of The Players Championship, his caddie and father-in-law, Steve Lucas, leaned on his man's golf bag and offered what could have passed for a bold prediction.

"He's got it together, pure and simple," Lucas said of O'Hair, who is 9-under par through 54 holes, 1 stroke ahead of Phil Mickelson, who shot a 69. "What you're seeing is what he is capable of. He's got all the shots. I think the stars are aligned."

O'Hair can only hope Lucas is right.

If he is, O'Hair, the 24-year-old third-year pro from West Chester, is on the brink of far and away the biggest accomplishment in his young golfing life - winning the so-called fifth major and $1.62 million.

"Really, tomorrow, all it is is just a round of golf," said O'Hair, doing his best to minimize the butterflies and the pressure. But it's undeniably there.

"Yes, it's the final round of the Masters," O'Hair went on, unaware he had just misspoken. "Yeah, I'm playing in the final group. Yeah, I'm playing with Phil Mickelson, but if I get caught up in all that stuff, I'm not going to play well."

Victory will not come easy. In addition to Mickelson, the No. 3 player in the world and a three-time major winner, O'Hair will have no less than 10 guys chasing him from no more than 5 shots back.

As they demonstrated today, pretty much all of them are capable of bagging birdies as if they are going out of style. Jeff Quinney surged into a tie for third at 7 under with an eye-popping 64. Luke Donald fired a 65 that moved him to 5 under.

And no question, if the weather holds tomorrow, and if TPC Sawgrass continues to play deliciously firm and fast, O'Hair's lead could be overtaken by any of a half-dozen players before he sets foot on the tee at 2:45 p.m.

Despite all that, O'Hair has every reason to feel he can close the deal, following up on his first and only win at John Deere Classic in 2005, the year he was voted rookie of the year.

After recently reuniting with the old swing coach he has known since his junior golf days, Steve Dahlby from Scottsdale, Ariz., O'Hair has been playing with more precision and more confidence. Suddenly, a guy who missed five of six cuts early in the season notched four consecutive top-15 finishes.

When he arrived here for The Players, O'Hair didn't promise a win, but he suggested he would be surprised and disappointed if he didn't pull off a strong showing.

He started with a par 72 on Thursday, then played his way onto the leader board with a 3-under 69 on Friday. Today, O'Hair was on fire, hitting fairways (11), greens (13) and needing only 25 putts.

He carded eight birdies in all, including the closing stretch of three in a row on three of the most famous and difficult finishing holes in golf.

The birdie at the 16th, a par 5, could almost be expected from a long-bomber like O'Hair. But a birdie was not expected at island green 17th, an infamous par 3 where golf dreams go to die.

There, with the wind swirling, O'Hair hit 9-iron from 147 yards, then watched in horror as the wind suddenly died. The television cameras caught O'Hair grimacing as he expected the ball to fly over the green and splash into the lake. Instead, a late gust caught it, and the ball came to rest five feet from the hole.

Nor was a birdie likely at the 18th, always ranked as one of the most punishing holes on the PGA Tour every year. There, O'Hair pounded a 3-wood 290 yards to the dead-center of the fairway. Then, with his stomach churning, he hit his approach from 167 yards to 12 feet. When O'Hair sank the putt to go 9 under, he took the outright lead.

Asked about the day's highlight, Lucas, the caddie/father-in-law, didn't mention any of those holes. He harkened back to No. 2, a par 5, where O'Hair pulled his tee shot into the woods and had to punch out to the middle of the fairway.

As O'Hair studied his next shot, his playing partner, Peter Lonard, holed-out his approach from 229 yards out for a double-eagle, touching off a roar from the gallery. When the hoopla died down, O'Hair calmly went about birdieing the hole himself.

"If ever there was a moment when the pressure was going to get to him, it was then and it was today," Lucas said.

To stave off dwelling on tomorrow, the plan tonight was for O'Hair and his entourage of wife, children and in-laws to head back to a house they rented for the week and relax. Eat, find a ball game on TV, talk about anything but golf.

"My dad is good about keeping it light," said O'Hair's wife, Jackie, juggling their children as she waited for her husband to finish the post-round process.

Minutes later, after the final interview was over, O'Hair was alone, drinking in the moment.

Was he surprised to be in the position he's put himself in?

"No," he said, smiling. "I've worked too hard. If I felt surprised, I haven't worked hard enough."

Contact staff writer Joe Logan

at 215-854-5604 or jlogan@phillynews.com. Read his recent work at http://go.philly.com/joelogan.