The two teams meet in Cologne on Friday night.
"We are aware that every detail of the final will be important," Lopetegui told the press.
"In terms of football, we must do what we always do and be prepared to overcome the difficulties that Inter will put us through, with their world class players.
"We are driven by enthusiasm and determination to play a great game.
"We are calm, with the tranquillity that we need to have.
"[It's a] final that we have worked hard to get to.
"The objective is to arrive on the pitch as best as possible, in every way, with balance and the right emotions.
"We are going to leave our lives on the field and [the fans] should not have the slightest doubt about this."