His preference for a quiet life was evident on Monday, when FC Barcelona's charter flight arrived at Edinburgh Airport. He did not go entirely unnoticed, as 40 or so folk had turned out to see him and his team-mates arrive, but he certainly bore the look of someone who wanted to get straight on to the bus, off to the team base, and out to the training ground as quickly as possible.

Messi, it should be explained, is not at all anti-social. He was polite to the autograph hunters who approached him five days ago, and he is a happy and committed member of the Barcelona squad.

Nor is there anything melodramatic or Garboesque about his desire to be left alone. He simply wants to be allowed to concentrate on the pursuit of excellence in his chosen profession, which is what brought him to public attention in the first place.

Or, to use the old cliche, he prefers to let his boots do the talking. They are, after all, pretty vocal.

That much was evident from the player's earliest years. He was born in Rosario, Argentina's second city, in 1987, and took the first steps towards professional sport as early as the age of five, when he started playing for a team coached by his father.

He joined his first recognised club, Newell's Old Boys, three years later, and for a time all was well. But, while his talent more than matched that of his peers, his stature did not, and it was found that he had growth-hormone deficiency.

Many of the most skilful players in football history have been on the short side, and Messi himself is no giant. Had he not received treatment for his condition back then, though, he would never have grown to a height which would be enough to help him hold his own.

To get that treatment, he had to leave Rosario, and Argentina, and head to Europe. After the briefest of appearances in a trial match, Barcelona had offered to sign him, and to pay for his medical treatment.

It was one of their shrewder investments. He responded well, and was soon one of the stars of Barcelona's youth set-up. He then spent one season with Barcelona B, the reserve side, and graduated to the senior squad in 2004.

In the four years since, Messi has grown to be a key player in the Barcelona squad and in the Argentine national side, and at 21 should keep on improving for years to come. An attacking midfielder who has a licence to rove around, he has the ability to ghost past opponents with a last-minute change of pace or direction, just as they think they have shackled him.

He has extraordinary vision, links well with his team-mates, lays on chances for others and is equally at home finishing them off himself. All he needs now is two or three more years' experience of playing at the highest level and he will surely prove to be the outstanding player of his generation.

If anything does prevent him from fully realising his talent, it will be his susceptibility to injury which may have its roots in that childhood illness. When he tore a thigh muscle against Celtic in March, for example, it was his fourth such injury in three years, and his sheer frustration at the recurrence was shown when he left the field in tears.

But that tendency to pick up knocks is at least partially counterbalanced by the rapidity with which he recovers his best form. He was out for six weeks after that thigh damage, and returned just before Barca's Champions League semi-final against Manchester United. The English club narrowly won the tie, but Messi won his own personal battle with Cristiano Ronaldo hands down.

For someone who cannot have been at full match fitness, it was a remarkable display of playmaking. The battle in question was not a direct one, for the Portuguese and Argentine players were invariably at different ends of the field. Instead, it was an unofficial fight for the title of best footballer in the world, and one which ended with the vast majority of judges giving Messi the verdict by a massive margin.

Ronaldo remains the more feted player, and in recent months has commanded more attention in the international media, partly because of his involvement in Euro 2008, but more significantly because of the saga of his dream move to Real Madrid. At a little over six foot, the United player is also far more imposing physically, and more likely to interest the editors of fashion magazines, than his shorter rival. Messi, 5ft 7in with his boots on, is a shilpit-looking thing.

But if the Argentine lacks Ronaldo's glamour, he is also free of the Portuguese man's glaring self-regard. You wouldn't catch Messi sunning himself in California while recovering from an injury. He'd be away in the treatment room, nagging his club's physios for a new prognosis in the hope that he could return to playing as soon as possible.

We should not underestimate Ronaldo's extraordinary talent, and if that move to the Bernabeu pays off there will be more occasions for a direct comparison between the two. For the present, however, there is little doubt that Messi has the edge. Indeed, while he has not been so dominant for any length of time that he can already claim to be one of the all-time greats of the game, Messi has steadily pulled away from the rest of the field. To an extent this is because as he has matured so an older generation has passed its best, but others closer to his own edge have also failed to match him.

His former clubmate Ronaldinho comes into the category of the once great. His compatriot Carlos Tevez, at 24 three years older, is one of those who has not kept pace.

Tevez was a revelation at the Athens Olympics four years ago, and Messi may yet perform the same role next month in Beijing. For the moment, though, he is at the centre of an increasingly rancorous row between Fifa, who insist he should be freed for international duty, and his employers, who do not think they are under any obligation to do so.

So far Messi's play has been unaffected by the dispute. Even allowing for the modest nature of the Hibs defence and midfield at Murrayfield on Thursday, he was outstanding, creating chances out of nothing with both feet, and constantly thinking ahead to seek out the next opening.

Today, presuming he plays, Dundee United supporters at a capacity Tannadice can expect to see something similar. An industrious and unassuming character, Messi appears perfectly suited to the hard-working approach which the new coach, Josep Guardiola, has sought to bring back to the club.

He can attempt the implausible – witness his Maradona-esque goal against Getafe in last year's Copa del Rey – but there is little cavalier in the way he plays. He takes more delight in killing off the opposition than in toying with him, as Hibs and so many other teams have found to their cost.