Diego Costa shows he is a one-man plan B intent on solving Spain's striker problem

Fernando Hierro said this week that he was an optimist who looks for the good in everything.

So when analysing Spain’s somewhat turbulent build-up to the World Cup the furore over Julen Lopetegui, the 53-year-old’s swift defenestration and Hierro’s subsequent appointment as his replacement, the optimist Hierro might have surmised that at least it had taken the microscope away from La Roja’s major on-field concern heading into this tournament.

For a team that is so unbelievably complete, that looks on paper to be almost footballing perfection, it has been a curious quirk that one of the most dominant and creative football teams of a generation have struggled to find an answer up front.

Since David Villa exited stage left from the national team there have been plenty of auditions for the role of Spain’s number 9 but nobody has ever really dazzled. Plenty of understudies but never a true star.

Diego Costa is quite clearly the most talented of the conveyor belt of forwards to have their chance, a hurly-burly centre-forward who has dominated in La Liga and the Premier League, eventually having his nationality fast-tracked in time for the World Cup in his native Brazil four years ago.

But Costa was not fit and Spain were not firing. That tournament was the pock mark on the flawless face of Spanish football’s golden generation but they did not allow it to scar, Spain has moved on and they played some good football at Euro 2016 before elimination to Italy before hitting top gear again in qualifying for Russia.

At the start of the decade it was tiki-taka that was the go-to phrase used to describe their football. Now merely mentioning Spain is to summon up technicolour images of bright crimson jerseys pinging the ball in triangles as if a training exercise. Their intricate dominance, a delicate asphyxiation of their opponents, has been an era-defining playing style associated with the great Barcelona side of Pep Guardiola and the Spain team that shared at least some of that DNA, but it has also caused its own problems since Villa’s departure as La Roja laboured to find someone capable of putting the finishing touches to their ornately prepared chances.

Costa is a barrelling hulk of a man who has thrived in Diego Simeone’s Atletico Madrid, Jose Mourinho’s Chelsea and, for one glorious season, Antonio Conte’s Premier League-winning Blues as well. All of those teams were reactive sides, teams whose first instinct is to drop and be compact in order to attack and counter into spaces. That, really, has always been Costa’s game and he’s sensationally good at it, rampaging around and occupying defenders, harassing defenders, nigh-on violating defenders in order to win the ball back and smuggle it home.

To be the No 9 in Spain’s system you really need to be a striker who is explosive in short-area situations, who can find half a yard and fire home when surrounded by the massed ranks of defenders that have formed a wall across the penalty area to deter Andres Iniesta, Isco and company. It is why the dinky but speedy Paco Alcacer – now hopelessly out of form at Barca but previously very effective with Valencia – was the right guy to start at Euro 2016 and top-scored in qualifying then. Alvaro Morata looked to have potential for the role but endured a rotten year in west London while Iago Aspas, for all his goals this year, just doesn’t seem to have earned the trust.

So Costa it was in Sochi, in the World Cup, against Portugal. For all his stylistic differences with what Spain do and how they do it, Hierro stuck with Lopetegui’s answer and went for proven quality over fit – a square peg in a round hole but those square pegs can still hurt if you catch them wrong.

And this is Diego Costa, so of course he caught them wrong. Just ask Pepe, whose face suddenly discovered in its schedule for the evening an unscheduled meeting with Costa’s forearm. Pepe flailed on the ground. Costa, surrounded by defenders and without a teammate in sight held up the ball, found a crack in the defence and drove the ball through it and into the net.

From what was a hopeful long ball – in the eyes of some, a betrayal of how Spain should play – Costa had turned water into wine. With Pepe still rolling on the floor he had turned water into whine. Portugal protested but Spain celebrated, Diego Costa the scorer and Hierro and predecessor vindicated.

When playing an opponent as tough as Portugal in a game as good as this on a stage as jaw-droopingly big, there will be things that go your way and things that don’t. On the night, Spain’s delicate build-up play and attempts at intricate creation fell flat, like an artist struggling for inspiration. But while the artist’s canvas lay bare, along came Costa with his customary sledgehammer to save the day, pummelling the canvas into a thousand paint-stained pieces and labelling it as a piece of art worthy of the Turner Prize.

Yes, on a day when the Spain way wasn’t working it was the striker who is as un-Spain as could be who found the key breakthroughs for them when it mattered; the first equaliser before Portugal had time to settle on their lead, the second equaliser from a set piece where Fernando Santos would have been sure his team had the nous to hold firm.

In the end this was a glorious game of football that will be remembered more for Cristiano Ronaldo’s hat-trick and the carefree exchanging of goals.

But for Spain, who deep down had some doubts about their team, they might just have found an answer to a question they’d struggled with. A hulking, unpredictable answer but an answer who saved their bacon.