Atletico host Arsenal in the first-leg of their Champions League semifinal.
Koke said on Tuesday: "Obviously, as the date approaches, there's nervousness, like on a first date. But when you go to the game, it all disappears.
"Then you just relax and play the game the way we've been doing. With enthusiasm.
"I feel like I'm really enjoying this season. You don't play in the semifinals every year, I don't know if I'll play in any more, but I'll enjoy them as I always have."
On Antoine Griezmann's final games with Atletico, Koke added: "If he leaves with the Champions League title, that would be incredible, but we're all motivated to win. This is a team. And the Champions League is the ultimate prize."
