And the way the 22-year-old held off a charging Tiger Woods to win the Honda Classic in Florida last night must have a lot of the same people believing he could be there for a long, long time.
Back-to-form Woods has never shot a lower closing round than his 62, but not even a birdie-eagle finish knocked the Northern Ireland off his stride to glory.
Nothing less than victory was going to be good enough to end Luke Donald's nine-month reign and, with Woods in the clubhouse one behind, McIlroy birdied the 13th, twice got up and down from bunkers on danger holes and parred in for a fabulous two-shot win.
The Holywood golfer becomes the second youngest world number one since the rankings were introduced in 1986. Woods was a year younger when he first got there at the 1997 US Open.
"It's very special," he said. "When I was 10 or 11, I was interviewed and said I wanted to be the best player in the world and I wanted to win majors."
He achieved the second of those targets at the US Open last June only two months after his traumatic 80 at Augusta.
Now he has achieved the first of them as well a month before he returns to The Masters to try to take his revenge.
Girlfriend Caroline Wozniacki, herself the tennis world number one until January's Australian Open, tweeted from New York: "Amazing performance. Tournament win and new world number one. Deserves a good celebration."
McIlroy, with his parents on hand to witness his third PGA Tour win, said: "It was tough today [Sunday], especially seeing Tiger make a charge.
"I knew par golf would probably be good enough and that's what I was trying to do, so to shoot one under is very nice and I was able to get the job done.
"My short game all week has been very good and it's what you need on a tough course like this. You know you are not going to hit every green."
He is the fourth European in a row to head the rankings following Lee Westwood, Martin Kaymer and Donald.
The coronation could have happened a week ago, but McIlroy lost the final of the Accenture Match Play in Arizona.
Nobody can deny his right to the top spot. Since the USPGA Championship last August he has played in 11 ranking events and finished outside the top five in only one of them.
That was the Dubai World Championship in December where he came 11th while suffering from suspect Dengue fever and during that run there was also his victory in the non-counting Shanghai Masters.
And he immediately targeted a long stay at the summit, saying: "I'd like to stay there for a while.
"As long as I keep playing good golf and have chances to win tournaments, then hopefully I'll stay up there.
"I feel the way I'm playing at the minute, the level of consistency, hopefully I'm going to be able to stay there for a while."
Woods, who had two eagles and four birdies in a flawless display that buried memories of his poor finishes in Abu Dhabi and at Pebble Beach earlier this season, said: "I've been hitting it like this, that's the thing.
"I hit it really good in the wind in Australia (last November) and thought there was no reason I couldn't do it again - and putt like I did the last two days. It came together.
"I figured I needed birdie-birdie to have a chance."
But eagle-eagle would not have been enough as it turned out.
McIlroy's putting has often been questioned, but it came to his rescue on the final day. On the front nine he saved pars from 13, eight and 12 feet and all day he did not miss once from under 10 feet.
Woods, who had been joint 18th and nine behind at the start of the day, finished joint second with fellow American Tom Gillis, while Lee Westwood burst from 27th to fourth with a 63 that was his lowest-ever score in America.
But it was McIlroy's day - and now it is his world too.