A sharp intake of breath, a moment’s pause, and then the inevitable: all across Edmonton’s Commonwealth Stadium, furious tapping on telephone keypads. Forty-nine minutes into Chile’s 2007 Under-20 World Cup win over Congo, the scouts had seen enough. This Alexis Sánchez had already shown them he could dribble, feint, beat his man and pick a pass. Now, after drilling a low effort across his body and into the bottom corner from 20 yards out, he’d demonstrated that he could finish too.

No point wasting any more time, they needed to know who this kid’s agent was, how much he would cost. The only problem was that Udinese had already beaten them to it. By more than a year.

The Cobreloa president Augusto González spoke of a “good piece of business” after agreeing to sell Sánchez to Udinese for a sum variously reported as anything up to $3m in April of 2006, but 15 months on it was apparent that the Friuliani hadn’t done too badly out of the deal either. Sánchez had since excelled during a year on loan at Colo-Colo and after his Under-20 World Cup showing several of Europe’s leading clubs made enquiries. A year later, after a further successful season out on loan at River Plate, Manchester United had a €12m offer for the player turned down.

If Sir Alex Ferguson saw in Sánchez a potential heir to Cristiano Ronaldo, in Chile he was being likened to Lionel Messi. Such direct comparisons are reductive by nature but there was some measure of truth in each. Like Ronaldo he played out wide but used pace and power to cut inside. Like Messi he has never allowed a lack of height to prevent him from imposing himself on opposing defences.

The player had not yet turned 20 when he finally made his Udinese debut but already back home he was an icon, nicknamed El Niño Maravilla (The Boy Wonder), and within a year a song of the same name would be dedicated to him by the band Tomo Como Rey. He had played a handful of games for Chile’s senior team, scoring in friendlies against Switzerland and Guatemala.

His stature was reflected in the comments of compatriot Mauricio Isla, who had moved to Udinese in the summer of 2007, having previously been a regular room-mate with Sánchez during their shared time with the Chile Under-20s. “For me it is a joy to play alongside him,” said Isla, “but also an honour.”

Sánchez did not need long to establish himself as a regular in Udinese’s first-team, but while there was steady improvement under manager Pasquale Marino, this season has brought another significant step forwards. The player had caught the eye once again playing on the right of a three-man attack for Chile at the World Cup, yet Udinese’s new manager Francesco Guidolin had seen enough over the summer to convince him that Sánchez could be even more effective playing through the middle.

“We took a gamble on Sánchez,” Guidolin told La Stampa this morning. “He had always played wide, but when I arrived I put forward the idea of playing him behind the striker [Antonio Di Natale]. From a central position he can be even more decisive … Playing as a No10, he is more unpredictable, harder [for opponents] to keep tabs on.”

It is a gamble which has paid off handsomely. Five goals from 19 games might look a modest return, but the fact that he has scored in each of the last four games suggests he is warming to a role with which he was initially unfamiliar. Sánchez has said that he is only playing to “40%” of his potential at present but even when he is not scoring the player has been performing a vital role for Serie A’s fourth-most prolific side. Only three outfield players in Serie A have received a higher average match rating from Gazzetta dello Sport this season.

His impact has certainly been felt by Di Natale. It seemed implausible before the season that the striker could, at 33, repeat his achievements of last season, when he topped Serie A’s goalscoring charts with 29 goals, but if Di Natale has already scored 14 in 19 games then that, too, is the result of the support he has received from Sánchez. The Chilean’s runs have consistently created space for his team-mate to exploit.

A partnership that showed plenty of promise before the winter break has flourished further since Christmas. Four goals against Milan at San Siro were followed by a further four away to Genoa this weekend, even if Udinese did get a helping hand this time from the Genoa goalkeeper Eduardo. The Udine-based newspaper Messagero Veneto likened their partnership to that of two of Italy’s most famous comedians when they wrote: “Totò and Peppino used to make people laugh. In Udine Totò and il Niño make people cry. Opponents.”

But the one thought that might bring Udinese’s supporters to the brink of tears is that Sánchez could soon be moving on. Both Inter and Chelsea have made enquiries during this transfer window, and though the team have insisted he is not for sale, the reality of modern football is that players who want to leave will usually get their way sooner or later. It will have come as a relief, then to hear Sánchez state in recent days that he is content to stay at Udinese a little while longer.

“I want ten goals [this season], this way I can help Udinese to get into Europe,” said the player when asked about his goals for the rest of the campaign. “Maybe even into the Champions League – why not? With the right mentality it is possible. And if we finish among the top four you can be sure that I won’t move.”

Leaving those scouts to curse once more their failure to move a little quicker.

Paolo Bandini covers Italian football for guardian.co.uk and Astro SuperSport, as well as The Score. You can follow him on Twitter @Paolo_Bandini.