A relatively unknown 18-year-old right winger of remarkable technical ability, apparently lacking the physical attributes to succeed in the Premier League but signed for big money by Manchester United.

In many ways, Amad Diallo’s arrival at Old Trafford from Atalanta for £19m – a fee that could rise to £37.2m – is reminiscent of Cristiano Ronaldo’s transfer from Sporting Lisbon in 2003.

There are a lot of differences too, though.

Whereas the Portuguese was signed, for £12.24m, after an impressive full debut season in the Primeira Liga, the Ivorian prodigy has only played four times for Atalanta in Serie A – none of them as a starter.

Granted, he scored a magnificent goal on his debut against Udinese in October 2019, but that clearly did not persuade the coach Gian Piero Gasperini to give him more opportunities.

What makes Diallo so special in the eyes of Manchester United scouts, then? Coaches who have worked with him closely and journalists who have followed his development talk about a winger of phenomenal attacking potential, a player who is disciplined, dedicated and extremely determined to reach the top.

“Amad has the same DNA as the ball itself,” Giulio Yanez Ghidotti, L’Eco di Bergamo correspondent who follows Atalanta’s youth-team matches, tells BBC Sport.

That is probably what his parents felt at a very early stage. Born in Abidjan, the largest city in Ivory Coast, Diallo moved to Italy with his brother in order to develop his talents and become a professional footballer.

The first significant stop, at the age of 12, was at Boca Barco, a tiny amateur club from Emilia in the north of the country between Parma and Bologna, named after the Argentine giants Boca Juniors.

“We didn’t discover Amad, but rather he just came to us. It was a great stroke of luck,” Denis Cerlini, the youth coach who trained Diallo at Boca Barco, tells BBC Sport.

“From the very first moment, it was evident the kid was special. He was very bold and quick, possessed great technique and a strong shot, and executed everything at great speed.

“Amad was popular in the dressing room. He made a lot of friends, learned Italian and seemed to be a very determined guy who knew exactly what he wanted.”

Diallo starred at a Christmas tournament and shortly afterwards was noticed by Giovanni Galli, the former Fiorentina, AC Milan and Napoli goalkeeper who played for Italy at the 1986 World Cup.

“A friend asked me to take a look at two guys – Amad and his older brother Hamed Junior Traore, who plays for Sassuolo nowadays. I worked at Lucchese in the third division at the time, and invited them for a trial with our youngsters,” Galli recalls.

“I quickly saw they were simply too good for us. Amad played with bigger boys and drove them insane with his dribbling. Therefore, I made a few calls to Serie A clubs in order to tell them about the guys. At Atalanta, I spoke to the sporting director Gabriele Zamagna, and they duly signed Amad.”

After arriving in Bergamo in 2015, Diallo was one of the standout players at the academy. He won the championship title as the major star of the Under-15 team, even though he was just 13.

Quickly climbing to the Primavera (under-19s), he continued to excel, and won the championship title there too, in 2019.

Shortly afterwards, Gasperini invited the rising star to train with the senior squad, and his new team-mates were impressed. They did not really enjoy playing against him, as their captain Papu Gomez explained. “Every Thursday we faced the Primavera and Diallo was very difficult to stop. He is just like Leo Messi, and we had to kick him.

“Amad is very creative and visionary, his dribbling skills are brilliant, and he is a team player as well,” says Corriere della Sport journalist Andrea Losapio.

“He can play anywhere across the front line, and his partnership with Dejan Kulusevski – a Juventus player nowadays – was outstanding at the Primavera.”

“Diallo is definitely one of the most interesting footballers of his age,” Tuttosport correspondent Giordano Signorelli adds.

“He wasn’t intimidated on his Serie A debut, and played very well on his Champions League debut against Midtjylland last month as well.

“He is extremely gifted technically, but lacks some physical qualities. I believe he can overcome those problems if he works on them.”

His lack of physical prowess appears an aspect Diallo – and indeed Manchester United – will need to be aware of.

“Physically, Amad wasn’t the strongest at Boca Barco, and his heading abilities aren’t good,” Cerlini says.

“He must add a few kilograms of weight in order to survive in the Premier League,” Galli adds.

But then again, those were the doubts that surrounded Ronaldo in 2003, and that transfer turned out to be fairly successful.