Madrid, Sep 3 (IANS): Spain striker Diego Costa has said that he has a debt to pay with the national football team.

The Brazilian born striker was a controversial inclusion in the 2014 World Cup squad for Spain after struggling with injuries at the end of the previous season. Once in Brazil those injuries prevented him being at his best and Spain slumped out of the first round of the competition, reports Xinhua.

Costa hardly contributed last season after joining Chelsea and suffering muscle problems during the campaign but Spain coach Vicente del Bosque has included him in the squad to face Slovenia in their 2016 European qualifying tie on Saturday.

It is a vital game with the leadership of their qualifying group at stake and Costa now feels the time has come to repay the confidence the coach showed in him.

"I feel like I am in debt with Spain, because I haven't done anything for us yet," he said in a press conference here on Wednesday.

"I have not justified the faith that the coach, (Del Bosque) showed in me and I know that I can contribute a lot more," commented Costa, who nevertheless admitted he had no regrets about choosing Spain over Brazil, who he had represented in a couple of friendly games.

"I never thought I have made a mistake in that, the only thing that bothers me is that I am not paying back what people have given me," the former Atletico Madrid star said.

Costa was also clear about what he needed to do in order to repay that faith: "Strikers need to score goals," he said. "I have to score goals and play well. If I am not at my best, the logical thing is for the coach to stop calling me, so what I have to do is find my form."