Spain coach Vicente del Bosque has backed Diego Costa to improve his form at international level.

The Brazilian-born striker has failed to score in his first five matches for La Roja after opting to play for them last year.

However, Del Bosque is confident that the 26-year-old will do "very well" for his adopted country.

"Diego has in front of him the challenge to show everyone that we have taken the right decision," he is quoted as saying by BBC Sport. "Maybe we are wrong, and it does happen in football, but I have a lot of confidence in him that he is going to do very well."

While he has struggled to find the net for Spain, Costa has scored nine goals in nine games for Chelsea so far this season.