Del Bosque: Casillas was 'only player' I didn't send thank you message

Outgoing Spain manager Vicente del Bosque has been opening up about his frosty relationship with goalkeeper Iker Casillas.

The veteran bench boss, who announced Thursday that he is resigning from his post following La Furia Roja's elimination at Euro 2016, made the decision to drop Casillas in favour of David De Gea for the competition, a move that upset the former Real Madrid icon.

Related: Vicente del Bosque resigns as manager of Spain

"With his teammates, he was OK, but with the coaching staff, his behaviour wasn’t good. His anger was directed at us," Del Bosque told Spanish radio station Cadena Ser, as translated by The Guardian.

Del Bosque's response? It was quite simple, actually: "That’s why he’s the only player I didn’t write to [upon leaving]."

Casillas, the starting shot-stopper for his country since 2002, holds the national appearance record, having won 167 caps for Spain. But his advancing age and declining form saw him superseded by the Manchester United goalkeeper, a decision Del Bosque admitted was difficult to make.

"For sure he is hurting or displeased with me and I understand that. He thinks we have done the wrong thing," he said. "But we have to be proud of a player who has 167 games with the national team. I don’t believe three or four games will hurt his resume.

"Casillas hasn’t disappointed me. I have a great appreciation for him. I have known him since he was nine years old."