Diego Costa of Spain ftakes on Slovakia's Norbert Gyomber (right) and Lukas Tesak (left) during the European Championship qualifier in Oviedo

Vencer y convencer, as they say here: win and convince. Spain did not just secure the 2-0 victory over Slovakia that saw them climb to the top of European Championship qualification Group C, they also produced the kind of performance that at times was as impressive as it was necessary. In doing so, they were led by Andres Iniesta and in particular by David Silva, whose superb pass brought the opening goal after just five minutes, and who led them throughout. The doubts had been suffocated early.

Most of them, anyway. At times, the defence was sluggish, while Diego Costa’s adaptation to the selección is still not complete and the whistling aimed at Gerard Piqué gave a negative note to this.

But the Manchester City playmaker began a wonderful display with a lovely ball, clipped over the top of the defence, to open the scoring and set Spain towards a victory that they needed – and not just for the sake of qualification. His pass curled towards the corner of the six yard box, where Jordi Alba was sprinting in. With the goalkeeper Matus Kozacik poorly positioned, the full-back headed in. And so it had began; when Cesc Fàbregas played the ball over the top of the defence for Costa to run unto after half an hour, it led to the second goal. The surprise was that it did not lead to more.

Costa has scored just once for Spain, against Luxembourg, and had said before the game that he has still done nothing for Spain, to whom he still owes a debt. Here was the opportunity. Costa chased Cesc’s pass but allowed the ball to go further across his body than he might have liked. Kozacik came towards him, but then backed away, standing up sharp, pulling out of the challenge. Costa, though, had decided that the Slovakian keeper would have no way out.

The striker hung his leg and tumbled. It looked like a dive, but the referee Damir Skomina pointed to the spot and Iniesta scored from it. It looked so easy; it had not been expected to be. Slovakia had won nine out of nine before tonight, Spain five out of six. There should have been little cause for alarm, particularly with this qualification format, and yet there was concern. Spain had been beaten in Slovakia and they came into the game second in Group C, three points behind Slovakia and level with third-placed Ukraine, who had just defeated Belarus 3-1. Defeat would have left Spain six points off the top of the group as they head to Macedonia in midweek, followed by Luxembourg at home in October and then the game that might well effectively become a play-off for a place at the European Championships in their final game: away in Ukraine.

Those were the statistics; then came the sensations. Spain had lacked the assuredness that had once defined them. Even in victory, this had felt more like the team that departed the 2010 World Cup early than the one that won it all. Some of the enthusiasm has waned and the pressure was significant.

If they did not win, there would be people waiting for them. For Vicente del Bosque, especially. When Slovakia won the first corner in the opening minute and Robert Mak ran clean through soon after, pulling his shot wide beyond Iker Casillas’s right-hand post the sense of nervousness returned. It did not last long; the goal came and the flow followed. Spain needed to win and to convince, and they did. With Silva playing centrally and Pedro swift and sharp; with Alba flying beyond them and Iniesta gliding through their midst, at times it was superb. The ball was moved quickly; some of the old pace and precision returned.

One particular move saw the ball moved across the pitch until Fàbregas’s attempted backheel came off his own leg. Another began with Iniesta pirouetting away from one man and Pedro spinning past another, racing away up the line. Neither came to anything, but that did not mean that they did not mean anything. An idea, a confidence, shaken of late, was restored. When Slovakia did take aim, Casillas saved. There were other scares but Spain survived them.

Spain might have conceded but they could have scored two, three, four more. Had Silva found the finish for another superb move, it would have topped it all. A neat move in the final minute almost yielded the third, even if by then the game was winding down. In the end, it was only two, but this was about more than just the scoreline. When Fàbregas had messed up his backheel he had not been the first to try one: you soon lost count of the flicks and the neat touches, the ball played round in little touches as if they were playing piggy in the middle on the living room carpet.

But if that sounds frivolous, it rarely felt that way, still less from Silva or Iniesta. Instead, on Saturday, more than any other night, it felt like they needed it, and something of the old Spain returned.