Glenn Moore: Fearless Rooney already drawing comparisons with the all-time greats

It was not just the stunning execution of his hat-trick that lingered in the mind after Wayne Rooney's remarkable Manchester United debut on Tuesday night. There was also the 18-year-old's preternatural certainty. From the moment he walked out at Old Trafford Rooney had an imperious bearing and awesome confidence which men 10 years older would have struggled to capture.

Maybe it was the fearlessness of youth, which top-quality older sportsman, having encountered the harsh professional realities of their calling, sometimes refer to in the same wistful terms they might remember a first love. Maybe, for Rooney has already endured two of the pitfalls which dog his trade - injury and tabloid exposure - it was simply that we were in the presence of genius, and he knew it.

Sir Alex Ferguson once noted that not every player, whatever their talent, could handle the in-built pressures of playing for Manchester United, adding that strikers were the most vulnerable. Pre-Ferguson, Ted MacDougall, Garry Birtles and Alan Brazil failed to do so despite being bought for large fees. Peter Davenport, whom Ferguson inherited, and Jordi Cruyff, Diego Forlan and the midfielder Juan Sebastian Veron, all of whom he bought, fared equally badly.

Rooney is different and, fittingly, George Best was among those who acknowledged as much yesterday. "You look at that performance and you have to say that's as good as anything you've ever seen," Best said. "He's just getting better and better. The lovely thing about him is his temperament - he loves the big stage and the sky is the limit for him, it really is.

"He's got to maintain that level of performance but there's no reason why he shouldn't. He's got everything going for him, he's looking the complete player at 18 years of age. He can handle himself, he has two good feet, he's good in the air. He's got it all."

Ruud van Nistelrooy was hardly less enthusiastic. "He is only 18 and knows all eyes are upon him, but he went out and did his own thing," he said. "That shows his character. To do that at his young age is fantastic. He is fearless."

Prime among those who have arrived at Old Trafford with a swagger was Eric Cantona but, although he was several years Rooney's senior when he joined from Leeds, even he did not announce himself so dramatically. Although Denis Law scored on his League, FA Cup, European Cup and Inter-City Fairs (now Uefa) Cup debuts, and Tommy Taylor, Bobby Charlton and Paul Scholes are among those to scored twice on their bows, it is necessary to go back 99 years to find United's only previous hat-trick debutant.

Charlie Sagar, whose treble against Bristol City kicked off a promotion-winning season, was an England international who had won two FA Cups at Bury before signing for United. More honours seemed inevitable but a knee injury forced him to retire at the age of 28.

Medical science is vastly improved but injury is just one of the caveats which must be borne in mind when considering Rooney's prospects. Ask a former Stretford End hero, Norman Whiteside, who played in the World Cup six weeks after his 17th birthday.

Whiteside is now a physiotherapist, a knee injury having finished his career at 26, but his fondness for a pint hastened his departure from United. Ferguson shifted Whiteside to end the club's drinking culture, and the player said yesterday: "If anybody's going to keep Rooney's feet on the ground, it's Sir Alex. He's the type of manager who won't let him get out of line. He knows how to handle players and Rooney will be frightened to overstep the mark."

Ryan Giggs, another teenage prodigy, but one who has survived to make more than 600 United appearances, said: "The club's responsibility is to ensure Wayne is still fulfilling his potential in 10 years' time, not just one or two. It's something the manager is very good at and he'll make sure Wayne is properly looked after."

Whiteside hinted at the problems Rooney could experience when he added: "He'll face great pressure 24 hours a day. If you go out for a beer, it's multiplied by 12. If you're seen walking down the road with a girl, you're having an affair."

Football's history is pock-marked with the pain of failed prodigies: think of Wayne Harrison, signed by Liverpool for £250,000 at 17 but who never played in the first team and is now an HGV driver; or a quartet of former United starlets, Andy Ritchie, Mark Robins, Lee Sharpe and Lee Martin.

Better precedents are those of Alan Shearer and Jimmy Greaves. Shearer scored a hat-trick at 17, against Arsenal on his full debut for Southampton. Greaves, who scored on every debut, for clubs and country, hit four goals in a game for Chelsea at 17 and reached 100 League goals before his 21st birthday.

Both went on to be very good players who approached, but did not quite achieve, greatness. The same might be said of Paul Gascoigne, a later developer than Rooney but similar in many ways.

Only time will tell if Rooney can take that next step and join the likes of Pele in football's Pantheon. If he can keep his off-field lifestyle under control, the possibilities appear infinite. The frightening aspect of Tuesday night, for future opponents, was that there were clearly aspects he could improve on. Several times he did not read a pass. He annoyed Gary Neville, who had taken up an excellent overlapping position. He ignored the better-placed Van Nistelrooy when shooting. Yet his run for his second goal, and his headed pass for David Bellion's goal, were among many moments which underlined his vision.

As teams learn more about him, and Tuesday's video will be studied from Munich to Madrid, they will attempt to channel his runs into innocuous areas and squeeze his space but, such are United's range of attacking options, opponents cannot afford to concentrate only on Rooney. Only those of us watching will have that luxury.