Following his performance against Manchester United, Inter know they have a star on their hands in 18-year-old Davide Santon

Meet Davide Santon. Known as Il Bambino to Jose Mourinho. An 18-year-old veteran of eight senior matches who has become the first teenager the Portuguese is willing to rely on since Carlos Alberto, who scored the opening goal when Mourinho's Porto beat AS Monaco to win the Champions League in 2004.

Santon is already described as "the new Paolo Maldini" by Mourinho, a manager not known for putting his trust in teenage players, and is also being compared to the supreme Inter legend, Giacinto Facchetti. He was Inter's best defender 10 days ago against ­Manchester United at San Siro when he frustrated Cristiano Ronaldo to help his team to a goalless draw ahead of Wednesday's Champions League last-16 return at Old Trafford.

"He's a great player and in 10 or 15 years when he becomes the new Maldini or Facchetti, with 200 or 300 Inter games under his belt, in that moment I'll remember his debut," Mourinho says.

"In my view Santon is a right-back who can also play in midfield, ­principally in the position currently taken by Javier Zanetti. His versatility will be very important in his career. For example, Beppe Bergomi played as a centre-back, on the right or left and now Zanetti can play pretty much anywhere. All this is because they have character and ­confidence.

"I believe an intelligent player knows how to adapt to different situations. ­Santon still needs to improve, ­obviously, and be a little less naïve at times. But these are details when discussing an 18-year-old who just needs to keep ­working hard."

The reference to Facchetti who played 476 Serie A games for Inter, won ­consecutive European Cups in the 1960s and the European Championship with Italy, is typical Mourinho. When he was at Chelsea he repeatedly told Frank Lampard he was the world's best player. When he moved to Inter he showered praise on Zlatan Ibrahimovic who, the manager said ahead of first leg against United, was better than ­Ronaldo.

Santon, clearly, is precociously ­talented. He drew a genuine compliment from Ronaldo, the Fifa world player of the year, after that game, which United dominated. "I was impressed by him – I enjoyed our match. There's no doubt he is a really exciting talent and a great footballer," Ronaldo declared.

The Inter president, Massimo ­Moratti, was equally impressed, ­noting how ­Santon had handled Ronaldo. "He's 18 years old and faced the greatest player in the world. He played with the ­professionalism, calm, focus and class of a big champion. Should he remain in this way, he'll grow a lot yet, and he's going to be fantastic."

One of the moments that impressed came against Dimitar Berbatov during a first-half foot race. Santon started a good yard behind the Bulgarian, but the right-footed left-back turned up the speed, dispossessed United's No9 and made an effortless clearance.

Mourinho said later: "I think it's right to talk about Santon, who did fantastically in what was his first match in the Champions League. We can no longer say he's just a great talent, he's already a great player."

Santon, who made his debut in ­January against Roma aged 17, is a native of the northern town of Portomaggiore, in the region where Milan's coach, Carlo Ancelotti, hails from.

He is also a rare product of Inter's youth system. While the club have signed 16 year olds including Newcastle 's Obafemi Martins, they have produced few ­players of note in the two ­decades since the ­emergence of Bergomi and Walter Zenga.

This, according to Bergomi who played 19 seasons at Inter and led Italy in the World Cup they hosted in 1990, is why the club are hoping to protect him from over-exposure in the media, a fate that has befallen Santon's 18-year-old team-mate, Mario Balotelli. "We are taking a different tack with Santos, we should shield him," says the man known as Il Capitano.

This seems to contradict the gush of outpourings from Mourinho. After Inter's victory in the most recent Milan derby in February, in which Santon played impressively, Mourinho brought his young defender into the press conference. He told the media to ask Santon questions because "it will be another two months before you can do so again", then left him alone for a first grilling. Santon was unperturbed.

"I didn't have any fears because as always my team-mates made me feel welcome, and they told me that they'd always be there for me," he said. "I would like to thank Mr Mourinho because he's ­allowing me to play immediately. He has shown great confidence in me, and has therefore allowed me to prove myself. People have said that I am the next Maldini, and though I think those ­comments are exaggerated, I am very happy with the compliments. I wish to have a career as brilliant as his."

The next gauge of Santon's ­ability comes in Part Two of his duel with ­Ronaldo on Wednesday.