Vicente del Bosque says he will be "stubborn" over calling up Diego Costa for international duty, even as Chelsea coach Jose Mourinho continues to blame Spain for the striker's continuing injury issues.
Costa, 26, has missed his club's four most recent games since the international break due to a hamstring issue, although he is expected to return to face Queens Park Rangers in the Premier League on Saturday. The former Atletico Madrid player was also briefly hospitalised due to a stomach virus during this absence.
Mourinho has regularly claimed it was wrong for Costa to play in La Roja's Euro 2016 qualifiers against Slovakia and Luxembourg in early October.
Spain assistant coach Toni Grande responded by arguing it would have been "crazy" not to call up a player who until then had been featuring and scoring in almost every game for Chelsea.
Del Bosque has now told the DPA news agency in Madrid that having persuaded the Brazil-born player to switch allegiance prior to last summer's World Cup, there was now no chance of turning back regarding selection.
"We have not had luck with Diego," Del Bosque said. "He did not arrive at the best moment, nor did the injuries he had help him. But in some things we are very flexible and in others stubborn. And in this we are stubborn.
"I do not know if we are correct or mistaken. But in these moments if we had not brought Costa into the national team, for sure we would have been criticised for not having done so."
Costa has had a frustrating start to his career with Spain after struggling at the World Cup, and eventually scored in his seventh cap with a close range effort against minnows Luxembourg. Meanwhile emerging Valencia centre-forward Paco Alcacer, 21, has scored in each of his three senior international starts.
Del Bosque said he had given no commitment to always play Costa -- or indeed other more established players such as long-serving captain and goalkeeper Iker Casillas -- as a new Spanish team emerges ahead of the European Championships in France in 2016.
"We do not have a 100 percent commitment, not with [Costa] or with anyone else," he said. "The games themselves will continue to be our guide. The important thing is we have players who are active. We cannot begin to suddenly prepare a new team. We must go bit by bit. Fortunately we have good material to work with. In different positions there are alternatives."
Spain's next games are a home Euro 2016 qualifier against Belarus in Huelva on Friday Nov. 15, and a friendly against world champions Germany in Vigo on Tuesday Nov. 18.