The Spanish custodian signalled the importance of Thursday's continental match and declared that the team will do its utmost to go through
Los Che must overturn a two-goal deficit if they are to progress to the tournament decider after suffering a 4-2 defeat in the first leg of the tie at the Vicente Calderon last week.
"We know it is going to be hard because we did not expect this result in the first leg," Guaita told reporters at a press conference.
"But we have a chance to go through, there are 90 minutes left and we will leave our souls on the pitch to reach the final.
"We are very eager to play the game on Thursday. We know that we will have a lot of fans in the stands who will be supporting us until the very last minute, and we will try to go through because entering a final is the best thing there is."
Valencia head into Thursday's game on the back of a 4-0 thrashing of Betis, while Atletico come off a 3-1 victory against Espanyol.