​Exclusive - On 31 August, with Barcelona 1-0 down to La Liga new boys Osasuna at El Sadar and 50 minutes on the clock, Carles Perez whips a ball into the box from the right. The Barça forward on the receiving end of the cross out-jumps his defender and meets it with a perfectly aimed header past Rubén.

The forward is not Lionel Messi, nor Luis Suarez. It's not Antoine Griezmann, nor even Ousmane Dembele. It's 16-year-old (16 and 304 days, to be precise) Anssumane Fati, Barcelona's youngest ever goalscorer and the third-youngest in La Liga history.

Anssumane Fati

A week earlier, Fati had become ​Barcelona's second-youngest ever debutant, as he made a late cameo appearance in the win over Real Betis. Only 18 days older than Vicenç Martínez way back in 1941, Fati had (like many defenders to come) skipped past Barça's B team altogether to make it into Ernesto Valverde's setup.

Amid all the talk of marquee summer signings, Griezmann and Neymar, it had seemingly gone under the radar that Barcelona were sitting on top of an incredible homegrown talent, fearlessly ready to stake a claim for a starting berth at the world's biggest club before most his age had even finished school.

A photo of Fati being embraced by a smiling ​Lionel Messi went viral after the youngster's debut. It was the tacit blessing that went around the world.

In the 5-2 win over Valencia, Fati rifled past Jasper Cillessen with his first touch and then turned provider for Frenkie de Jong moments later. After the game, Valverde insisted the youngster's explosive progress was simply 'not normal'.

After that win, SPORT's front page asked, 'what planet did you come from, Ansu?'

It seemed an only semi-joking question. Wonderkids are two a penny in the modern game but nearly every starlet comes ready-made with a dossier full of information from Twitter punditry to YouTube highlight reels. However, this baby-faced phenom had seemingly caught everyone off guard.

Born in the West African former Portuguese colony of Guinea-Bissau (last ranked 123 in the world by FIFA), Fati is the son of Bori Fati, a former footballer who had left his home country for Portugal and later Spain in search of a brighter future.

After settling in the small town of Herrera in the Andalusian province of Seville, Fati senior's sons (Ansu and Braima) joined the local football team Escuela de Fútbol de Herrera, the free youth programme for thousands of children in the catchment area and youth set-up for regional side CDF Herrera. 

10-year-old Ansu's first coach there was Jordi Figueroa (pictured at the top), a man with over 10 years' experience, who had on occasion seen some of his young charges go off to Sevilla, Malaga and the likes over the years, but he never seen a talent quite like this. 

On first sight, did he expect young Ansu to be a star?

"Yeah, but not this quick," Figueroa tells 90min. "It was very obvious he had talent. He was a totally different kid. He had already learned a lot in his country. It was very surprising to see a child who was already so different from the rest at such a young age. 

"He already had all the physical and technical qualities of someone much older."

(Above: Ansu Fati in action for Herrera) 

Figueroa reveals that Fati was so 'not normal', as Valverde would later put it, that they went straight down the ayuntamiento (town hall) to check his documents to make sure he wasn't lying about his age. He wasn't. 

"His level of play just didn't correspond to his age, so we checked in the register of the town hall itself that the data was real. After that, it was confirmed. Because of his ability, we put him in the higher age group."

As an insight into Fati's preternatural technique, Figueroa continues, "His father told us that in his childhood over in Guinea, he learned to play with a ball that he made by rolling up socks together until they formed a ball. We were all touched by that detail.

"His teammates used to learn from him in the training sessions." 

The Fati family still has a house in Herrera, a town of fewer than 7,000 inhabitants, where Ansu has become as much of a local hero as he is back in the Sao Paulo neighbourhood of Bissau where he was born. The teenager, who is officially Spanish after being granted his passport this month, serves as a welcome inspiration for the next generation of would-be superstars in Herrera.

Figueroa drops in that Fati's idol during his two years with Herrera was (like everyone, he stresses) ​Cristiano Ronaldo, although (mercifully for Barcelona fans) he never saw the youngster in a Real Madrid CR7 shirt. 

However, remarkably for a player so dominant at his age group, Fati apparently lacked the perceived selfishness of his hero.

"The most typical thing that he would do," Figueroa remembers, "is to recover the ball in defence run all the way to the opposition penalty area, then look for a teammate to set up to score. He liked to score himself but, when it came down to it, it was never the most important thing for him. He liked to assist his teammates.

"In the semi-final of one tournament, I remember he was looking for an option to pass but there was none, so he went around and set himself up for a Chilena (bicycle kick). It was an incredible goal." 

Anssumane Fati

On Fati's best position, Figueroa adds: "It depends on the needs of the team, but he can be used in any position. He can play on either of the wings or up top as a number nine. His movement greatly imbalances the defence and he offers so much support to all his teammates."

Figueroa is still in contact with the boy who left Herrera just five years ago and has since rocketed to superstardom, revealing his message to Ansu after his debut against Betis. 

He said: "I spoke with him after his debut to congratulate him and wish him all the luck in the world and keep calm. I told him, now you must stay calm and not disturbed by your the phone, you must be a little saturated and you must return to normal."

'Normal' is not something that comes easy to Ansu, it seems.