There are portraits that precede greatness, snapshots of youthful genius. The boy with the indie-band bangs celebrating on Ronaldinho's back, the bleach-blonde teen with blaugrana braces leaving a trail of Inter defenders in his wake.

Almost exactly 20 years separated Lionel Messi's first goal for Barcelona and Lamine Yamal's sensational Champions League semi-final strike on his 100th appearance for the Catalan giants last Wednesday.

Yamal, a month younger than Messi was when he lobbed the goalkeeper from Ronaldinho's scooped assist to become La Liga's youngest scorer in 2005, has already won a European Championship with Spain and a La Liga, Copa del Rey and Super Cup with Barcelona.

"I don't want to compare myself with the best player in football's history," said the forward before his stunning individual performance against Inter, but conjecture around whether he can emulate Messi is natural.

The stats show Yamal's trajectory since his debut aged 15 years and 290 days is going up faster than either Messi or the other superstar of his generation, Cristiano Ronaldo.

Yamal hit a century of Barcelona appearances two months shy of his 18th birthday. By the same age, Messi had scored once in nine senior games for Barca while Ronaldo had netted five goals in 19 games for Sporting.

Yamal has 22 goals and 27 assists to his name, plus four more goals in his 19 appearances for Spain. Neither Messi or Ronaldo made their international debut until they turned 18.

It took Messi, who made his debut at 16, until shortly before his 21st birthday to hit the 100-game mark in Barcelona colours, scoring 41 goals in the process.

But they were the first of an incredible 672 goals for the club, to complement the eight Ballons d'Or, one World Cup, two Copas America, four Champions Leagues and a huge haul of domestic silverware.

"It is not normal," says former Barcelona midfielder Mark van Bommel of Yamal's rise. "That's why everyone is talking about him. [But] to reach the number of Messi, that's not easy. Even for a guy playing at 17."

Messi was the small boy who arrived from Argentina aged 13 needing growth-hormone treatment, the one Gerard Pique revealed team-mates at La Masia thought was mute because he "said nothing to us for the first month".

"Messi was always very cautious in the way he approached things - rivals, team-mates, managers - always very respectful," explains Spanish football expert Guillem Balague.

"But he would be the one putting the mental frame to those that came new. If they were from the lower ranks, he would protect them but push them.

"When Neymar arrived, he got the message: You are Brazilian, we know you like to express yourself a lot, but there are certain things you have to do here to become an important player for Barcelona."

Yamal grew up around 20 miles along the coast from the Nou Camp between the city of Granollers, where his mother lived, and Mataro, where his father was. He celebrates by making the number 304 with his fingers, the last three digits of his postcode in the Mataro neighbourhood of Rocafonda.

Remarkably, there are pictures of baby Yamal being held by a 20-year-old Messi during a photoshoot for Barcelona and Unicef in 2007. Seven years later, that baby was training with the club. By the age of 12, Spanish publication Marca was already comparing him to Messi.

Barcelona even broke protocol by bringing Yamal to live at La Masia - usually the rooms go to players from outside Catalonia and taxis are provided for local youngsters. Just over three years after moving in, Yamal made his debut against Real Betis.

"Lamine, they put him in La Masia. Why? Because with the coaches there was someone who could model his way," explains former La Masia coach Pau Moral, who says Yamal "had not had an easy environment". "Now he is in the correct way because Barca helped him a lot."

Yamal has since moved out of the Barcelona residence, buying an apartment not far from the training ground.

"Lamine Yamal couldn't have been more different to Lionel Messi," says Balague. "Since he was a kid he liked to joke inside the changing rooms, he liked to express himself.

"The fact his parents separated a long time ago and his mother has been the lighthouse in terms of values and behaviour, his father is almost more like a friend - that allowed a player like him to have the freedom to go beyond what is expected.

"A good example of that is Cristiano Ronaldo - he had no references and he thought he could fly and that he could be the best in the world and no one said to him 'no, you have to go to university etc'."

Balague describes Yamal as "completely fearless", which came across in Yamal's first news conference before last week's 3-3 Champions League semi-final first-leg draw with Inter.

"I left all my fears in the park of my neighbourhood," said Yamal, before responding to those who criticised his celebrations following Barca's Copa del Rey triumph against Real Madrid last month. "While I keep winning, they can't say much."

"I have never heard anything like that," says Balague. "It is very much like Cristiano Ronaldo behaviour - thinking 'I am the best, so it is not a problem'. But he is still a kid in so many ways."

Balague says when the electricity went down in Spain last week, Yamal, Gavi and Fermin Lopez took the opportunity to stroll around town with their hoodies on, before they were spotted.

"This is what he will do sometimes, not realising the impact," says Balague. "He went recently to Rocafonda and he realises he cannot return there any more because he has become a legend. He has come out of the district. He has conquered the world."

The late Kobe Bryant once told a story about Ronaldinho introducing him to a player he said would be the greatest of all time. "You what? You are the best," replied the basketball star. "No," said Ronaldinho. "This kid here is going to be the best."

Messi was 17, but those around him already knew they were in the presence of a star.

He joined a squad containing World Cup winners Ronaldinho, Juliano Belletti and Edmilson, stars such as Samuel Eto'o and Deco, and homegrown gems Carles Puyol, Andres Iniesta, Victor Valdes and Xavi.

The following season, Barcelona won La Liga and the Champions League - though Messi missed the final through injury - their first triumph in Europe's elite competition since 1992.

"We won the Champions League and La Liga with Ronaldinho in his prime," says Van Bommel. "He was on such a level that he could do everything on his own. We could just defend and let him inspire the attack, we knew we would win every game."

It is, of course, hard to compare players across eras. Yamal has emerged at a different Barcelona, where the club's financial situation has prompted them to turn again to their esteemed youth system.

It was after Ousmane Dembele left for Paris St-Germain and Raphinha was suspended for the second game of last season that Yamal earned his first start. Now he is the star.

"As a player and a talent, I think we are in front of the best player in the world now," says Moral. "Nobody does what he does. It doesn't matter if he is 17 years old. Lamine is a player who you feel when he wants, he can do something special."

Yamal has scored five times in this season's Champions League, while his 44 shots and 78 dribbles are both the most on Opta's records for a teenager in a campaign.

The earliest such data available on Messi is from 2006-07, when he was 19 and made 21 dribbles at a rate of 4.9 per 90 minutes, compared to Yamal's 7.2 this term. However, only three times in 14 subsequent seasons at Barcelona did Messi drop below Yamal's current average in Europe.

Messi missed a chunk of that 2006-07 season with a metatarsal fracture but still clocked up 26 La Liga appearances, scoring 14 goals with a shot conversion rate of 23% and creating 38 chances, which led to two assists.

Yamal, two years younger, has played 31 league games this season, scored six goals, made 12 assists and created 57 chances, though he has had almost twice as many shots as Messi did with a conversion rate of 5%.

"What we are seeing from Lamine Yamal is extraordinary and the impact it has had in world football is completely out of the ordinary and unexpected," says Balague.

"Barcelona players look at him for solutions. Certainly other players felt - especially when they went 2-0 down against Inter - that Lamine Yamal was the solution."

That is a question only time can answer.

"Certainly, we have to say he is ahead of Messi as it stands," says Balague. "But to be 15 years right at the top, influencing every final he played, that is something that requires a lot of consistency, luck and a strong mentality for when things go wrong.

"At the moment, everything is going well and this is the biggest impact Lamine has had - he makes us look forward to watching Barcelona, look forward to seeing him. He lifts us from our seats, makes us shout and scream when he does something."

Moral remembers watching Yamal decide youth cup finals, including his own "remontada" against Real Madrid. Now he is doing it on the grandest stage.

"Who expects a guy 16, 17 years old can play not just in first division, but in Barca... and can do something like the other day in the semi-finals of the Champions League or in the summer in the Euros?" Moral says.

"This guy is a kid, he is unbelievable. Honestly, I don't know where his top is, but we are in front of one of the greatest players in the future, I am sure.

"For me, Messi is the best in history. But if everyone involved with Lamine helps - the environment, friends, family, sometimes you get an injury - if everything goes well, if he takes good decisions and works like he is, I don't want to say better than Messi but he is on the way..."

Van Bommel says Barcelona's 2006 Champions League success "was the beginning of the Messi era", one built around La Masia talent with Messi at its fore. Now there is a sense Yamal could lead the latest batch of young stars into a new dynasty.

It's what Moral and others who coached at La Masia have been waiting to see come to fruition.

"We said it would never happen again. And look, 10 years later, we are in the same situation," Moral beams, recalling watching Yamal, Gavi, Alejandro Balde and Pau Cubarsi, and says there are more to come.

"When they touch the ball, you feel something special as a coach. Lamine, pfft, if one player at 12 years old has the capacity to make you crazy in training, it's like 'wow!'

"Barcelona is doing very good things - they invest in La Masia, in players, in talented coaches. Now it is normal to see players of 16, 17, 18 years old, which is unbelievable.

"When Xavi was in the top level, he was 26 or 27 years old. These guys are 17 or 18 years old so imagine in 10 years where they can arrive?"

Yamal is the star of this crop, a world-beater at 17.

Barcelona hope when the curtain one day comes down on his Nou Camp career, it will be with a legacy to rival Messi's.