He says Spain's style dates back to before the 2008 European Championship win, and claims Madrid were the dominant force back then.
"Anyone who has followed the national team a little will remember where our style of play comes from," he told Chilean newspaper El Mercurio in an interview.
And Casillas remembers that only three Barcelona players featured in the Euro 2008 final against Germany.
"If we start to remember a little bit further back in time, only (Andres) Iniesta, Xavi and (Carles) Puyol were Barcelona players in the final of the European Championships against Germany," he said.
"That Spain is associated with Barcelona's play is a good thing because the team has achieved great success, but the national team is not just about Barcelona's success; it's about the success of the rest, too."