Madrid - Spain can take a big step towards securing the right to defend their title in France next year when Slovakia travel to Oviedo on Saturday.
The European champions face Slovakia with a 100 percent record in qualifying Group C.
Vicente del Bosque's men trail the Slovakians by three points in the battle to top the group thanks to their 2-1 defeat in Bratislava in October last year.
However, victory in Asturias and another three points when Spain visit Macedonia in midweek will remove any nagging doubts that the holders could spectactularly miss out on the opportunity to win the tournament for a record third consecutive time.
Spain's preparations have been overshadowed by David de Gea's failed move from Manchester United to Real Madrid as both clubs pinned the blame on each other for not formalising the deal before the transfer window closed at midnight on Monday night.
De Gea has been included in Del Bosque's squad despite not playing a minute of competitive action this season as United boss Louis van Gaal claimed the 24-year-old's concentration had been affected by his proposed move.
However, that lack of match practice meant the former Atletico Madrid stopper was unlikely to have started in any case with captain Iker Casillas expected to maintain his place despite ending his 25-year association with Real Madrid to join Porto.
Casillas was badly at fault for Slovakia's two goals in their only competitive defeat since their miserly showing at the World Cup last year.
Yet, it is at the other end of the field Del Bosque's side have tended to struggle in recent times scoring just four times in their last five outings.
In the search for goals, Del Bosque has turned to Diego Costa with the Chelsea striker returning to the squad for the first time in nearly a year despite his less than stellar start to the season at club level.
Costa has failed to shine in a Spain shirt since turning his back on Brazil, the land of his birth, to represent the defending champions at the World Cup.
Indeed his only goal in seven appearances came against minnows Luxembourg on his last outing an international level.
"I feel I owe a debt to the coach and the teammates that have given a lot for me," said Costa.
"The only thing that bothers me is that I haven't returned the warmth shown to me by the Spanish national team. It was the right decision, of course it was, and now that I feel good, there are no injuries and it is a new situation."
Costa is expected to start up front as Juventus striker Alvaro Morata misses out through injury, whilst Paco Alcacer has yet to find the net for Valencia this season.