For someone who's on top of the world, Trevor Immelman has spent a lot of time looking up the last few days.

One day after becoming the Masters champion, Immelman was courtside at Madison Square Garden for the Boston Celtics' 99-93 victory over the New York Knicks. He was invited to the Celtics' locker room at halftime by coach Doc Rivers, who wanted his team to shake hands with a champion.

"There might have been a trainer that was shorter than me," said Immelman, who stands 5-foot-9 with the help of golf spikes. "But I'm standing next to Paul Pierce and Kevin Garnett, and I'm belt-high. It's pretty incredible that human beings are that damn big."

Tuesday morning, he was taken by limousine to the Empire State Building for a photo shoot atop the tallest building in Manhattan.

There also were TV and radio interviews on the agenda, including his reading of a Top 10 list on the "Late Show with David Letterman" and an appearance on "Live with Regis and Kelly."

The highlight, though, might have been halftime.

Born and raised in South Africa, he now lives in Orlando, Fla., and loves the NBA. Immelman is a regular at Orlando Magic games. Even so, he found it surreal to be among giants in green jerseys, listening to them praise a golfer in a green jacket.

"They were telling me they were in Atlanta and watched the end of the tournament, and that they were proud of me," Immelman said. "It's kind of weird to see superstars congratulate me on something I've done."

There has been a lack of sleep, and little time for all this to sink in.

"These are things that don't happen to ordinary people," Immelman said.

All because he did something extraordinary.

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Not since Seve Ballesteros in 1980 had a player put his name atop the leaderboard after the first round and stay there over four days at Augusta National, a course where Immelman correctly noted that there's "a disaster around every corner." He became the first South African to win the Masters since Gary Player, his idol and inspiration, 30 years earlier.

And he joined Tiger Woods, Jim Furyk, David Duval and Vijay Singh as the players to win a major by three shots in the last 10 years.

"That's pretty hefty company," Immelman said. "It will take some time before that sinks in."

Until his Masters victory, Immelman said his greatest golfing achievement had been winning the Nedbank Challenge four months ago in South Africa, an event he regards one notch below the majors.

That celebration wasn't quite like this one.

Immelman wasn't getting a whirlwind tour of New York, rather he was in a hospital listening to doctors explain that the pain he felt in his rib cage turned out to be a tumor in his diaphragm. Within a week, he was having his back cut open to remove the lump, and only later did he learn it was benign.

"Since I was a young boy, very deep down I felt I was good enough to win a major," Immelman said. "As crazy a game as golf is, you go through periods where you doubt yourself. After the surgery, I pretty much had to start at Level 1 again and build my game up again. It was unbelievable timing to find my form last week."

"Unless you're Tiger Woods," he added, "you don't know how often that opportunity presents itself."

The opportunity arrived Sunday, and Immelman seized it _ just as Zach Johnson did at the Masters a year ago, just as Angel Cabrera did at Oakmont, Michael Campbell at Pinehurst No. 2, Rich Beem at Hazeltine.

All won majors with Woods lurking on the back nine.

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"I don't think it's ever easy to win a major in any era," Immelman said. "As you say, I'm playing in Tiger Woods' era. This guy is frightening in what he gets done and how he gets it done and the ease in which he gets it done. To win a major while he's playing _ and he's playing at his peak _ it's a hell of an achievement."

The trick will be getting grounded once he comes down from the Empire State Building.

Only three major champions over the last 10 years — Shaun Micheel, Ben Curtis and Lee Janzen — won nothing else but a major that year. Immelman might not have been anyone’s pick at Augusta National, but he was part of a B-list group of favorites along the lines of a Justin Rose, Paul Casey, Stewart Cink or Adam Scott.

That's not to suggest Immelman is going to win the Grand Slam. He was the first to concede that.

But golf is largely about confidence, and Immelman now is equipped with memories of a week at Augusta National where he posted three straight rounds in the 60s, and answered a lot of questions about himself in a final round of 75.

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After a miserable chip on the 11th, he made a 20-footer to save par. After chopping up the 12th, where he had to make a 4-foot putt for bogey, he answered with a birdie to build a five-shot lead. And after his worst swing of the day, a 7-iron into the pond for double bogey on the 16th, he bounced back with a bunker save for par on the 17th.

The two-day trip to New York was all about publicity, but it gave Immelman time to take stock of what he accomplished and how far he had come. His parents went back to Florida with Immelman's 1-year-old son, leaving him and wife Carminita to tour the Big Apple.

They began dating when Immelman was 14.

"We went to the same high school, but she was a grade ahead of me," he said. "She's grown up with me in this sport. We've been through everything together, from lugging our luggage to the tube station in London to driving in a limousine in New York.

"Pretty damn crazy."