Pep Guardiola was a proud man as he sat in the stands at the home of his club's great rivals, Real Madrid, nearly a year ago. He was proud of the performance that had earned his Barcelona team a 2-0 victory, a crucial and ultimately definitive result in the title race. He was proud, too, of the man who had scored the second goal. "It is time," Guardiola said gravely, "that we had a serious talk about Pedro."

Pedro, the youngster Guardiola had kept at the Camp Nou against the advice of the technical staff; the kid he had taught himself. The player with whom he had won promotion from Spain's regionalised third division, with its 360 teams, and who, less than two years later, had just scored in the most important club match of all.

Pedro Eliezer Rodríguez Ledesma is irreplaceable to Barcelona. He is a World Cup winner and a world record holder – the only footballer to have scored in six different club competitions in a calendar year. He had won everything before his 23rd birthday. But Guardiola had a point when he said Pedro should be taken more seriously. Almost a year later, he still has.

That day last April, while Guardiola was sitting at the Santiago Bernabéu, he explained: "Pedro has become vital for us, absolutely fundamental. He is a role model, a great. He always exceeds expectations."

And yet those expectations remain surprisingly low. While Catalonia might be talking seriously about Pedro, it can feel as though few others are. Beyond Barcelona there is still an assumption that he is one of few players in the Barça team who is not really that good.

Pedro denies it publicly, but others insist that during the clásico Cristiano Ronaldo looked at him and said: "And who are you?" Even if the story is apocryphal – and it may be – it says something. Others would ask the same thing. When Fernando Torres left Liverpool for Chelsea, many wondered why he did not hang on for a bid from Barcelona. The answer was simple: there would not be one, because of Pedro.

When Guardiola arrived at Barcelona, the technical reports recommended that, because of the disbanding of the C team following Barcelona B's relegation, Pedro return home to Tenerife, where his father pumps petrol at the forecourt he built with his own hands. But Guardiola wanted a winger and Pedro was the one. Together they won promotion with Barça B. Guardiola was promoted to the first team. Pedro and Sergio Busquets joined him. Soon, they were in the Spain squad: both started against Holland in the World Cup final. As Guardiola puts it, they went from Cassà de la Selva – the only place Barça B lost that season – to world champions in 18 months.

Pedro played 14 games in the first division and 27 in the second in 2008-09. He spent the week training with the first team only to play with the second team. "I was unfair on him and yet he never complains," Guardiola says. "He scores for the B and comes back on Monday, happy as anything."

Soon, there was no way back. In 2009 he scored in the league, the Champions League, the European and Spanish Super Cups and the Copa del Rey. He headed in the 88th-minute equaliser that helped Barcelona win the World Club Championship and set that six-competition record. By the end of last season, he had scored 12 in the league.

"He has an eye for goal," says Guardiola, who considers him as deadly as Messi in the penalty area. Madrid should know: he has scored in his past two games against them. "If Pedro was Brazilian," Guardiola famously said, "he'd be called Pedrinho and we wouldn't have enough money to afford him."

When he opened the scoring against Hércules two weeks ago, it made Pedro the first Barça player in 14 years to score in six successive matches. When he opened the scoring against Espanyol, it was the fifth time he had started with Villa and Messi – and the fourth time Barça hit five. In their next five games, they scored 17. He has scored 21 in La Liga, the Champions League and the Spanish Cup already. And he has seven league assists. But for Guardiola there is more to Pedro than goals.

Few coaches are as tactically obsessive as Guardiola, as keen on two key points: positioning and pressure. Pedro offers width on either side: stats show that while Villa and Messi drift to the centre, Pedro opens up the pitch. He is fast, genuinely two-footed, and his movement is startlingly intelligent and so often decisive.

"My job is to go outside and create width," he says. "Or come in between the centre-back and the full-back. I have to fill in the space quickly, coordinate with the midfielders and make sure no one runs a counterattack on us."

Guardiola has just one complaint: that Pedro is "too humble". He does not take on his man enough and is too ready to drop off the ball to Messi. Yet that is the flip side of the same coin that makes Pedro so valuable. It is the dynamism, intelligence and solidarity that most pleases Guardiola. Pedro chases down defenders, forces mistakes, wins the ball – and rarely loses it. That pressure pulls the whole team forward: the coach describes him as "contagious". Pedro, says Guardiola, is "the image of the team".

And not just any team.