By James Horncastle 

Last updated: 01 May 2014, 22:16 BST

Now you see it. Now you don’t. A trio of Napoli players thought they had Mateo Kovacic surrounded. How wrong they were. Shuffling the ball between his feet, he wriggled free, escaping Houdini-like from an improvised blue cage to force a save from goalkeeper Pepe Reina. The little magician didn’t limit his performance at San Siro to one trick. He had others up his sleeve.

Before the interval, Kovacic released Mauro Icardi through on goal. It was as though a dove not a ball had fluttered from his right foot. Then towards the end, he made one of his assistants Yuto Nagatomo disappear then reappear behind the Napoli defence where he bore down on Reina’s goal. It came to nothing but again Kovacic had brought his audience to the edge of their seats, provoking a sharp intake of breath then applause. They love this kid.

He arrived unexpectedly a year or so ago. Inter had forced Wesley Sneijder out following his refusal to accept a pay cut. They had sold Philippe Coutinho to Liverpool. A change in system indicated that there was no longer a place for a playmaker behind the strikers. And so the money from their exits was supposed to be spent on a box-to-box midfield player, Paulinho. The amount they raised, however, wasn’t enough. Inter had to withdraw their interest and risked looking foolish.

In Sneijder they’d deprived themselves of a star, although a fading one. Meanwhile AC Milan were adding one of their own: Mario Balotelli, Inter’s former prodigy. They needed to respond. Kovacic was the answer Inter came up with. It was a clever one. Since 2010, it’s not often you can say that about Inter.

Few of their fans had heard of Kovacic let alone seen anything of him. That meant they were reliant on what they were told. For some he was a Robert Prosinecki regen. Others had him down as the second coming of Luka Modric. Then no less than Zvonimir Boban made this comment: “He has the potential to become better than me.”

The mystique suited Inter on several levels. It meant they could present Kovacic to their supporters as the next big thing in football. Why else would they hand him the symbolic No.10 shirt, a garment worn in the past by Ballon d’Or winners like Luisito Suarez, Lothar Matthäus, Ronaldo and Roby Baggio? It was taken as a measure of their belief in Kovacic and quite the stamp of approval.

The idea of him that had been created in supporters’ minds was a powerful one. Inter had given them something to look forward to, a future to get excited about. Its personification was Kovacic. Understandably there has been a clamour for him to play ever since and initially he did.

It was feared that Walter Mazzarri would not blood youngsters from the club's Primavera.

Andrea Stramaccioni, the former coach of Inter’s Primavera, who had been appointed supposedly to bring through some of the players with whom he had won the Next Gen series, eased Kovacic into the first team fold. But when he was sacked and replaced by Walter Mazzarri last summer, some in the Curva Nord were already concerned for Kovacic.

Over the years a perception has developed of Mazzarri as a coach who does not trust in youth. Opportunities were few and far between for a talent like Lorenzo Insigne under his tutelage at Napoli. Kovacic has also found it tough until recently. Injured in pre-season, he missed the tactical sessions Mazzarri considers fundamental and has had to play catch up. But as spring arrived the sense grew that Kovacic wasn’t getting enough of a chance.

He was averaging 44.5 minutes a game. Of his 24 appearances before the last international break, 15 were as a substitute. He started and finished a game only four times and didn’t look like getting many more after Mazzarri seemed to blame him for the opening goal Inter conceded in the Derby d’Italia against Juventus. Frustrated, Kovacic expressed his dissatisfaction before Croatia played Switzerland in March.

Reports began to emerge that he was seriously contemplating a move at the end of the season. It led to an outcry. Il Corriere della Sera’s Fabio Monti sent out a warning that Inter risked making the same mistake with Kovacic as they had made in 2001 when they gave up too soon on a certain Andrea Pirlo. Mazzarri appears to have belatedly heeded it.

For the first time this season, Kovacic has started two games in a row. Satisfied that he has taken on board how and where to play when Inter are in and out of possession, Mazzarri has played him for the full 90 too. “I feel a lot better,” Kovacic told La Gazzetta dello Sport. “If I play from the start I don’t feel like I have to overdo things as happens when I come on. Now that I have a first team shirt, I won’t give it up.”

Man of the Match against Napoli, for Interisti the Austrian-born 19-year-old merits the billing as a little Mozart ahead of the Derby della Madonnina at the Scala del Calcio this Sunday. Before Inter and Milan’s last encounter, La Gazzetta had lamented how on the stage where there was once so many virtuosos, the sound emanating from it this season has hardly been classical and more like the din made by pots and pans. When Kovacic orchestrates the play, however, sweet music fills the air.

Still yet to score for Inter, there is one opponent in particular against whom he’d most like to get his first goal. “Milan,” Kovacic insists. To see if he does why not join us for the Milan derby on BT Sport this Sunday. It’s live as part of the European Football Show from 6.45pm.