AC Milan travel to the Nou Camp tonight with a two goal advantage from the first leg, but vice-president Adriano Galliani has warned the job is far from done.
Goals from Kevin-Prince Boateng and Sulley Muntari stunned a subdued Barcelona in the first leg at the San Siro, however there is a confidence in Catalonia that the tie can be turned around.
It is a view Galliani agrees with, pointing out that the strength of Barcelona means it is impossible to be relaxed heading into the match, particular with Lionel Messi among the ranks of the opposition.
"We can't go into the game thinking we'll be fine just because we've got a two-goal advantage," he told acmilan.com. "We are going up against the strongest team in the world who have a monster like Leo Messi who scores all the time. Let's hope he takes it easy on Tuesday night."
Galliani is predicting an epic challenge for his side, who will be with out striker Giampaolo Pazzini.
"One thing is certain - it will be another great challenge, an infinitely difficult challenge. It's always nice to play Barcelona but we will be going into an incredibly heated atmosphere."
On the injury to Pazzini, who has scored 13 goals in Serie A this season, Galliani is confident other members of the squad can fill the void.
"It's a shame, a real shame that he's been ruled out," the Milan chief added. "Will we go there to play for him? Yes, for him too.
"We have lost an important striker but whoever replaces him will do well."
Tonight's match kicks-off at 7.45pm GMT with the winner going into the hat for Friday's quarter-final draw in Nyon.