The midfielder has urged fans to "dream big".
He told AS: "You have to have enthusiasm and desire to work and dream big. I always say that the club sets objectives for us, but we have to be more ambitious internally and want to go for more.
"Our people want to see us winning titles, we want to win titles and hopefully this season we have the chance to win some."
On Alvaro Morata's departure for AC Milan, Koke added: "Thank you for the work you have done over the years. It's a shame because I have a very good and very close relationship since we started when we were little. Wish him the best. Beyond that, we need people who want to be at Atleti, who are 100% focused on the club to compete and win.
"And if any teammate is not, like he has done, who has raised his hand and decided and asked the club to leave, nothing happens. We will try to bring another teammate who is 100% ready to compete."