If Jim Furyk ever breathes heavily or feels something thump in his chest, his closest friends wouldn’t know. Of all the players to endure a round with Tiger Woods as the final pairing at a major championship, Furyk might be best equipped. He doesn’t smile. He doesn’t frown. He just plays.

Graeme McDowell’s heart might be racing, right now, as he sips a cup of coffee or a pint of Guinness. Watch him play a round under the pressure of a U.S. Open, and there are all manner of fidgets and smirks, sarcastic eye-rolls and genuine, wide smiles.

Disparate outward attitudes, apparently, are just fine here at the Olympic Club, because Furyk and McDowell lead the 112th U.S. Open after 54 holes at 1 under par — the only players under par with just the final round remaining. Their advantage is two over Sweden’s Fredrik Jacobson and three over England’s Lee Westwood, South Africa’s Ernie Els , Belgium’s Nicolas Colsaerts and American Blake Adams.

The central characters, then, are established. Both are former U.S. Open champions. Either could add another trophy Sunday.

“It’s wide open,” McDowell said.

Where, though, is Woods? The most stunning development Saturday — as McDowell, Jacobson and Els shot 2-under 68s, as Westwood bested them with a 67, as 17-year-old Beau Hossler managed an even-par round, and as birdies were removed from the endangered species list — is that Woods disappeared. He shared the lead after 36 holes, then posted an out-of-nowhere 75 that was filled with sloppy, baffling shots. Instead of being a front-runner, he sits 4 over.

“I’m definitely still in the ballgame,” Woods said. “I’m only five back. That’s definitely doable on this golf course.”

The way Woods played Thursday and Friday, when he went 69-70? Sure. But not the way he played Saturday, when the butchery began early. He bogeyed the first, the third, the fifth and the eighth. He hit into the trees at the monstrous, 671-yard 16th. He dumped a shot from the middle of the fairway into a greenside bunker at 17. And he stubbed a chip shot from an unenviable lie by the side of the green at 18. Generally speaking, on a day when 20 players shot par or better, a mess.

“I kept leaving myself in tough spots,” he said.

He is now in the toughest. Nine previous times, he has held at least a share of the lead at the midway point of a major. Eight times, he has converted. But if he’s to do that here, he will have to come from behind, a manner in which he has won zero of his 14 majors.

“There’s going to be a bunch of guys there with a chance,” Woods said.

Whether he is one of them is up for debate. Others are in the thick. Take the unexpected appearance of Westwood, who buried a 30-footer at 18 to match the low round of the day. He has never won a major, but his recent record in them is remarkable. In the last 11, dating from the 2009 British Open at Turnberry, Westwood has finished tied for third or better six times.

“I pick little bits out of all of those, but the main thing is just to go out there and believe that I’m good enough,” Westwood said. “I must be. I keep getting myself in contention often enough.”

He will play with Jacobson in Sunday’s penultimate group. McDowell and Furyk, the final pairing, each spent time saying anyone in the group immediately behind them is in contention.

“There’s a bunch of people piled up and close to us,” Furyk said. Yet their lead is two. As they played with each other over the first two days of the tournament, each took time to compliment the other’s game and personality. They are thinkers, Furyk, 42, the methodical type, McDowell, a decade younger, a bit schizophrenic. But their approach Sunday will hardly differ, even if their mannerisms seem completely opposite.

“On a golf course like this, you have to go from spot to spot,” Furyk said. “It doesn’t have to look or be fancy. It has to work.”

What they did worked Saturday. When Furyk, playing with Woods, opened with bogeys at 1 and 5, he didn’t sulk or scowl. The 2003 U.S. Open champ strode forward, his expression changing not a bit. He came back with birdies at 7 and 11, gutsy saves from greenside bunkers at 12 and 14, and a round that had his listless, emotionless efficiency written all over it, a 70.

“Obviously, I like being up front in the position I’m in,” he said.

McDowell, the Northern Irishman who became enormously popular here after his 2010 win at Pebble Beach, heard encouragement from the galleries all day, with several offers of a post-round pint.

“People are stereotyping me,” he said. “. . . Kind of under some illusion I like a cold beer.”

Any cold beers would have to wait until Sunday night, because McDowell knows he has more work to do, with Furyk at his side. He admitted to being nervous prior to teeing off on Saturday — as he was for the third round at Pebble Beach. But he tried to get clinical about it. In a way, he tried to transform into Furyk.

“You’ve just really got to be unemotional as possible as you can on this golf course,” McDowell said. “I tried to go out today and have two emotions” good emotions and neutral ones.”

That way, he could overcome an errant tee shot at No. 9 that led to his only bogey of the day and come back with a birdie at 10, another at 12, another at the last.

And that left him with a night to try to get some rest, to try to slow his heart rate, to try to match Furyk. Because that approach beat everyone in the field through three rounds, Woods very much included.