Bayern Munich coach Pep Guardiola during the press conference in Munich, Germany, May 11, 2015. [Photo/Agencies]

Nevertheless, Mueller is under no illusions of what to expect with Barcelona - and Lionel Messi in particular - currently in supreme form.

"We need passion, determination, the support of the fans and to believe in ourselves," he said.

"The goal is for things to turn out the way they did against Porto, but we know that won't be easy.

"We have to find the right mix of better attacking and to be more calm on the ball, which was our problem last time against Barcelona.

"We have nothing to lose against Barca and this is how the players and the coach are approaching the match.

"We'll give it a try, it is not over yet. We will give everything until the referee blows his whistle."

Messi was the architect of Bayern's downfall in Barcelona with two goals before setting up Neymar for their third.

The hosts are determined not to concede a goal, but neither can they focus purely on keeping Messi subdued.

"The problem isn't Messi alone, the problem is the whole Barca team," said Bayern defender Rafinha.

"Everyone knows how good he is, a player like that can do virtually nothing all game and then turn the match with one pass, but it's not just about him."