Lamine Yamal was the story before kick-off and is dominating conversation long after the final whistle too.

The 18-year-old returned to Atlanta hoping to start his first World Cup match, having been limited to just 19 minutes in Spain's shock goalless draw with Cape Verde.

Luis de la Fuente insisted that cameo was part of a longer-term plan, with Yamal still carefully managing his recovery from the hamstring injury he suffered in April.

Fit enough to start against Saudi Arabia, his impact was immediate.

Even before his first touch, the impact he had on the atmosphere was remarkable.

Thousands of fans wore his name across their backs. Every time his face appeared on the big screen, the stadium roared.

Spain's young star had not yet touched the ball, but already lifted the occasion.

When he did, he transformed the first half of the match.

Spain had promised greater intent, to play with boldness, pace and fearlessness. They delivered that in a 4-0 thrashing of Saudi Arabia, with Yamal at the centre of it all. Where their previous outing lacked urgency, this performance was vibrant, direct and full of conviction.

"You can give a bit of advice but when you see a player like this with the confidence and freedom, he can create a lot of things that I couldn't teach," his former Spain team-mate Cesar Azpilicueta told Match of the Day.

"When he is on the pitch he knows how to create chances, take on defenders and where to get the ball. From there, he is growing every single game."

Sharp, fearless and brimming with confidence, Lamine Yamal drifted past defenders with ease and injected life into Spain's attack. There was a sense of inevitability about what would follow.

When the breakthrough came, it was fittingly his.

A low cross flashed across goal and Yamal arrived at the back post, sliding in to convert and score his first World Cup goal.

The Atlanta stadium erupted as fans cheered, danced and chanted Lamine's name. This was the superstar they had come to see.

Guillem Balague, speaking on 5 Live, said he saw Lamine Yamal walking out looking around like he had just conquered the world.

"Is it arrogance? Or confidence? A mixture of both," he said. "He is the chosen one, he wants to be the chosen one.

"He is so happy in the role he is taking on as leader of the team. He told me once that his joy when he plays football is seeing the same reaction when he used to play five-a-side.'

Yamal became the seventh player in history to score at a World Cup before turning 19, and only the second aged 18 or younger to open the scoring in a match, the other being a 17-year-old Pele for Brazil against Wales in 1958.

Wayne Rooney was highly complementary of the teenager - the comparisons to Lionel Messi inevitable.

"For Messi and Cristiano Ronaldo, the application and dedication they've had is the reason they are both playing in this World Cup," the former England forward told Match of the Day. "They have done everything right. Hopefully Yamal can do that.

"What is really impressive to me is when Messi came in to that Barcelona team, there was some top players and a crossover with Ronaldinho.

"[Yamal] has come in to the Barcelona and Spain team and it is his team, he is the main man.

"Everyone is looking to him to win. [He was] a big part of winning the Euros and will be a big part of this World Cup. That is what really impresses me, he is taking the pressure on at such a young age. You hope he can do that for the next 15, 20 years."

Yamal's magic set the tone and more goals followed.

"You hope he has the right team around him to help, because he is a global superstar. You hope he is allowed to keep doing what he's doing," added Rooney.

Mikel Oyarzabal struck twice in quick succession, capping a remarkable opening spell. With two goals and an assist, he became only the second player since 1966 to be directly involved in three goals within the opening 25 minutes of a World Cup match.

It was a complete contrast in performance from his previous match against Cape Verde, where he had gone the opening 30 minutes without a single touch, the first player in World Cup history to do so.

This match was different. Now, Spain's dominance was reflected on the scoreboard, and they looked every bit like European champions.

Yamal's work was done by half-time, withdrawn as a precaution with one group game remaining against Uruguay.

Speaking on Match of the Day, Thomas Frank said: 'Lamine Yamal always wants the ball. The determination and application to keep playing at the highest level, but also how can he stay humble enough when he knows everyone is saying he is the new coming superstar.

"How can you stay humble enough? That is going to be the big thing."

Spain will continue to manage his fitness carefully, because a fully fit Yamal could prove decisive.

By the time he turns 19, the World Cup final will be less than a week away.

The question now is simple: will he be the reason Spain get there?