Stranger still is that he doesn't seem fazed, perhaps because his age (20) matches the odds (20-1).
McIlroy already has shown in small doses that he is capable.
He comes from Holywood -- a coastal town in Northern Ireland, not to be confused with the glitz of Los Angeles -- and already is easily recognized by his freckles and curly brown hair that tumbles out of his cap and over his ears. He made his British Open debut as a teenager two years ago at Carnoustie and opened with 68 on the toughest links in golf.
And without knowing it, he can put on quite the exhibition.
On a surprisingly sun-splashed day along the Ayrshire Coast, McIlroy found a flat part of the putting green Wednesday, and his caddie marked off 8 feet with a chalk line. The kid rapped three balls at a time, stopping to chat, constantly smiling, not really paying attention.
He made 105 putts in a row, seemed to lose interest, then moved on to another hole 30 feet away.
One reason he is getting so much attention, beyond the talent that allowed him to win the Dubai Desert Classic this year and rise to No. 22 in the world ranking, is constant search for someone to challenge Tiger Woods.
Even at golf's oldest championship, the focus turns to youth.
McIlroy will be playing the first two rounds with 24-year-old Anthony Kim, who is No. 15 in the world and an explosive talent. Martin Kaymer, the 24-year-old German, is coming off consecutive victories on the European Tour and can became the first player since Seve Ballesteros in 1986 to make it three in a row.
Among the "older set" are 29-year-old Sergio Garcia and Adam Scott, who turns 29 today when the British Open begins.
So far, it has been a hopeless pursuit.
Woods set an obscure PGA Tour record two weeks ago when he won his AT&T National at Congressional for his 53rd victory this decade, topping the previous record of Ben Hogan, who won 52 times in the 1940s.
His 12 majors this decade is another record.
Woods is 0 for 2 in the majors this year since returning from knee surgery, both times giving himself a chance on Sunday, both times finishing in a tie for sixth, four shots behind Masters Tournament champion Angel Cabrera and U.S. Open champion Lucas Glover.
One thing McIlroy has in his favor is having never faced Woods.
"It's been more inspirational for me, rather than disheartening, that this guy is coming to win every major he plays," McIlroy said.
It all unfolds today at Turn-berry, with Woods teeing off with 17-year-old Ryo Ishikawa, another young player with hopes of someday challenging the world's No. 1 players.
The biggest generation gap is five-time champion Tom Watson (59) playing with British Amateur champion Matteo Manassero (16).
Watson won the most famous Open at Turnberry in 1977, the "Duel in the Sun" against Jack Nicklaus. His biggest thrill was going head-to-head against the best and beating him.
That's what the kids from this generation face. "There is that element of who is challenging Tiger," Watson said.
"Well, you're going to have some people challenge him and beat him. But he's beaten everybody a lot more than anybody's ever beaten anybody in this game of golf. He's just on a run that's been unparalleled."
WHERE IT IS: Turnberry, Scotland (7,204-yard, par-70 Ailsa Course)
WHEN IT STARTS: The opening round of the 72-hole major championship begins today (7 a.m., TNT).