The future of golf is a shambling, disheveled working-class Northern Irish kid with a swing like a butter knife. Rory McIlroy tries to dress country club-neat, but his pants bag around his hips, and his shirt comes untucked, and his black curls spring rowdily from under a cap pulled low over his young eyes. While the rest of us gasp in the heat and stress of the U.S. Open, he takes the steps of Congressional Country Club two at a time. That’s what being 22 years old with a bullet will do for you.

If his final round Sunday goes anything like the previous three — he has the second-largest 54-hole lead in the 111-year history of the tournament — he will win his first major championship, and we may one day say the game’s next great player was born as a champion at the Bethesda course. This is the fourth straight major championship McIlroy has led, though he has yet to complete what he so brilliantly starts.

“First of all, I like his moxie,” said Jack Nicklaus, who holds golf’s record with 18 major championships. “I suppose that is the right word. I like the way he carries himself — his moxie.”

A McIlroy victory is no certain prospect — the last time he was in a similar situation he shot a boyish 80 two months ago in the final round of the Masters. But McIlroy’s performance this week has reaffirmed this much: He is an appealing comer with the face and loping limbs of a baby spaniel, whose stunningly pure ball-striking and modest good manners mark him for inevitable stardom.

“There’s no point in everyone saying you’re going to be a major champion when you’re not one,” McIlroy said earlier this week. “You have to go out and prove them right and prove to yourself that you deserve to be one. It’s very flattering and it’s great that people are saying these things about me but I need to do it first, and I haven’t done it yet. I just need to go out and play the golf that everyone thinks I’m capable of. And if I can do that for four days, then hopefully I’ll be sitting in front of you guys on Sunday night and maybe saying, yeah, maybe I could be a multiple major champion.”

It’s a typically unspoiled sentiment from McIlroy, whose attitude comes directly from his Northern Irish relations. His mother Rosie, a former factory worker, is known to tell him, “Get over yourself.” The family hails from Holywood, a village just five miles east of Belfast where his grandfather Jimmy worked the docks repairing shipping cranes, and where the McIlroys still live.

“It’s a very close-knit town where all the people know each other, and a very friendly town,” says Michael Bannon, the head pro at Bangor Golf Club in County Down, who is the only golf teacher McIlroy has ever had, and who has known him since he was a baby.

McIlroy’s father Gerry grew up in a council house, a version of government-built affordable housing, which sat just 200 yards from the Holywood Golf Club. Gerry worked as a bartender at the club, and would take Rory to the course in his stroller.

By the time Rory was just 21 months old he could hit a golf ball with a small plastic club his father gave him, and according to family lore he hit a 40-yard drive as a 2-year-old. As a 4-year-old he was chipping balls down the hallway of the family home and into the washing machine, at which point Gerry took him to Bannon, then the assistant club pro at Holywood. Though Gerry was a near-scratch golfer, he had the sense to turn his son over to someone else.

“He gave him over to me and kind of let the reins go,” Bannon said from Northern Ireland in a phone interview.

To pay for the lessons Gerry and Rosie worked multiple jobs. Gerry cleaned the facilities at a local sports club in the mornings, and did double shifts managing the bar at Holywood.

“They put everything into him,” Bannon says. “Gerry was a hard worker; he did a few jobs in the old days.”

The McIlroys had no doubt it would be worth it, their son was so clearly a gifted prodigy from the outset. At 8, he was the youngest member of the Holywood Club. At 9, he won a world championship for his age group at Doral in Florida. By 11, he shot even par at Holywood, and at 15 he played his first pro event in the 2005 British Masters. At 16 he showed what he was fully capable of, when he obliterated the scoring record with a 61 at Royal Portrush, considered one of the most demanding courses in the world, a jagged layout along the dunes of the Irish Sea. That performance is why no one in Northern Ireland is at all surprised with the size of his U.S. Open lead. Record after record has fallen as he has matured into a professional.

McIlroy’s ball-striking in the Open has been so superb and so overpowering that he has earned comparisons with Tiger Woods, who is chasing Nicklaus for the title of greatest player ever. Although he is just 5 feet 9 and 161 pounds, he has driven the ball a whopping average of 312 yards. He’s done it with a level head and an even-tempo.

“It’s funny to me, you know, it feels quite simple,” he says.

But the combination of strength and precision has overwhelmed the field, not to mention been beautiful to watch. By the time he reached the second tee Saturday, the huge galleries that followed him were loudly chanting, “Let’s go, Ro-ry!”

“Yeah, it was incredible; the support that our group got out there was fantastic,” McIlroy said afterward. “It’s nice when you get nearly a standing ovation on every green you walk up onto. Hopefully I can just give them something else to cheer about tomorrow.”

Only one thing remains for McIlroy to prove: that he can fulfill his talent by finishing in one of golf’s four annual major championships. It’s the last challenge but it’s also the most difficult one.

After being told that other professionals were comparing him to Woods and that Padraig Harrington went so far as to say that McIlroy — not Woods — would be the one to break Nicklaus’s majors record, McIlroy laughed

“Oh, Paddy, Paddy, Paddy,” he said. “You know, I’m still looking for my first one. That’s all I can say. I’m looking for my first one. I’ve put myself in a great position to do that tomorrow, and then we’ll see what happens from there.”

In his previous experiences with a lead, nerves got him and his swing got too fast. Last year he shot a 63 in the first round of the British Open at St. Andrews, tying the record for the lowest-ever in a major, but followed it with an 80. In his Masters debacle, he came so undone he hit a ball out of bounds. But McIlroy impressed all observers with his class in congratulating the winner Charl Schwartzel, and in admitting his weakness.

In the wake of the Masters he went to play in Nicklaus’s tournament, the Memorial, in Dublin, Ohio, and after a charity clinic he sat down with history’s greatest golfer for a brief counseling session. The two had gotten to know each other better during a 2010 tournament in Palm Beach Gardens, Fla., over a long lunch, when McIlroy spent an hour and a half quizzing Nicklaus on his methods for practicing, preparing and closing out tournaments.

“He was worried that he couldn’t finish, couldn’t win,” Nicklaus said in an e-mail interview. “I said not to worry about it. Instead of shooting 36 or 37 the last nine holes, one day you’ll shoot 32 or 33 and win. It’ll just happen. Keep playing; keep your nose to the grindstone. You don’t have to try to push something to happen.”

After the Masters collapse, Nicklaus reiterated his message. He kidded McIlroy that he would whack him if he gave away another major; then, he reassured him.

Next, Nicklaus gave him a few words on the subject of pressure.

“Pressure is what you live for,” he said. “You want to have pressure on you. You don’t want to come down to the last hole needing to make par to finish 20th. You want to come down to the last hole with pressure on you to win. Everyone is going to put pressure on you. That’s going to happen in life. If you are going to be successful, you’re going to have pressure.”

It appears that he has dealt with it. McIlroy’s 68 in the third round was all about solid golf under pressure. It gave him a lead of eight strokes, the second-greatest margin ever in a U.S. Open, behind only Woods, who led the 2000 Open by 10 strokes.

Eighteen more holes stand between McIlroy and his first major victory — that crucial one that seems sure to lead to so many others.