A deal appeared close before Atletico reached the Copa del Rey final and also the Champions League quarterfinals.
Griezmann said: "I always wanted to do everything to accomplish great things here.
"I feel very good here, on the pitch. It's true that at the beginning, it was more difficult to manage. With work, a passion for football, things became easier, and so did the support of my family."
Concerning the derby against Real Madrid this evening, he added: "I don’t really think about it. I have a lot of fun.
"I'm having a blast, I'm playing more than at the start of the season. I savour the present moment."
The No7 aims to win the Copa del Rey while going as far as possible in the Champions League: "The two, we cannot choose. You have to do both."