The former Arsenal winger said: "All the critics that are around and the pressure that existed has not affected me at all.
"I signed for Atletico, I know what it means to wear this shirt, I know that I am with a great club and nothing else. Last season I defended another shirt, the one of Real Madrid, and right now this is the one that I defend and I am going to give everything to it."
He added: "Javier Aguirre is a trainer who gives you freedom and great confidence. He is an impressive coach who wants the best from you every day."