The Italian reporters in Manaus were quick to poke fun at English ignorance. After watching Matteo Darmian play a starring role in Italy's World Cup-opening 2-1 win over England, they filled their newspapers with accounts of bewildered foreigners scrabbling to find out who the full-back was.

Only a few were honest enough to admit similar conversations must be taking place back home. If Darmian was not exactly an unknown quantity in Italy – he had played regularly and well for Torino over the previous two seasons – then he was far from being a household name. His first cap had arrived only a fortnight earlier, in a tune-up game against Ireland. To the casual fan, he was just another anonymous full-back from a mid-table team.

The moment was captured in an article by Andrea Sorrentino for the newspaper La Repubblica. "How old even is this Matteo Darmian?" he wrote, posing rhetorically a question being asked in earnest all over the peninsula. "He must be very young, who has ever heard of him? Is he 20 years old? Maybe 19? Wrong … Matteo Darmian is 24. In fact, he's 24-and-a-half."

How could such a talent have flown under the radar for so long? Darmian, a product of the Milan youth system, had made his debut at 17 but played only four top-flight games in three years before being farmed out to Padova, Palermo and Torino, who made his signing permanent in 2013.

His journey is reflective of Italian football’s enduring mistrust of youth. It is far rarer to see a teenager granted an extended run of games in Serie A than the Premier League but it is also true that coaches did not always know what to do with him.

When Milan first brought Darmian into their academy system at 10 years old, they viewed him as a midfielder. After a time, they converted him into a central defender but when he failed to grow as tall as they had hoped, they nudged him out to full-back.

As Darmian tells it, his footballing role models shifted in line with these positional changes – from Clarence Seedorf, to Alessandro Nesta to Paolo Maldini. After being promoted to the first-team squad in 2007, he had the chance to train with all three.

“To say that I tried to steal something from them would be pretentious,” he told Gazzetta dello Sport in January. “Let’s say that Clarence taught me what personality is, Sandro elegance and Paolo professionalism.”

Darmian possesses all three attributes in abundance, though the latter might be his defining characteristic. In discussing life after football, Darmian has said he would be interested in becoming an interior designer, noting that: “A designer is good if he understands what people want from him, he does not impose what he wants.”

These are words to make a coach go weak at the knees, although we should note he has had other career ambitions. At the end of his first trial at Milan, the 10-year-old Darmian was asked what he would like to do if he was not to become a footballer. “I replied ‘a pizzaiolo’ for no real reason. Maybe just because I really like pizza.”

Stories such as that one led Gazzetta's Andrea Elefante to remark on Darmian's "profound normality". During their interview, the journalist presented the defender with a set of cards representing different topics of conversation and invited him to discard the three he did not want to talk about. "I'll get rid of fear, politics and vices," replied Darmian, "because I don't have any."

From another man such words might have sounded insincere, but from Darmian they are credible. Off the pitch, he is strait-laced to the point of almost seeming a little rigid. He keeps a tidy house, abhors tattoos and cites bad drivers and his long-term partner Francesca’s habit of smoking indoors as the things that stress him out the most.

If he has grown into a tremendous footballer, it is in part because he displays the same fastidiousness on the pitch as he does off it. Darmian is precise in his passing and disciplined in applying tactical instructions.

His versatility remains an asset, and even last season he played the odd game at centre-back, but he has thrived in Turin as a wing-back. Few players anywhere tend to both their defensive and attacking duties so diligently. Darmian won more tackles per game than any Torino team-mate last season, and also created the joint-second-most scoring opportunities.

He has a knack for rising to the big occasion. If that England game last summer were not proof enough, then consider the fact that, of the four goals he scored for Torino last season, one arrived in the club's historic win over Athletic Bilbao at San Mamés – a ground where no Italian side had won before – and another in April's 2-1 victory over Juventus. The Granata had not previously beaten their city rivals for 20 years.

Louis van Gaal will appreciate the luxury of knowing his new acquisition can play on either flank. Most of all though, he should be delighted to have acquired such an abundantly-talented player at such a modest fee. Manchester United are understood to be paying £12.9m plus a potential £2m in bonuses.

That is more than 10 times the sum Torino paid to acquire Darmian but even for a player most of Italy barely knew 12 months ago, it could be an absolute steal.

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