Barcelona stand-in coach Jordi Roura says his team must not rush things in Tuesday night's Champions League last-16 second leg against AC Milan, even though they know they must score at least twice to have any chance of progressing.
Goals from Kevin-Prince Boateng and Sulley Muntari gave Milan a 2-0 win in last month's first leg at San Siro, and Barca go into the game knowing that no side in Champions League history has ever overcome a two-goal first-leg defeat without the benefit of an away goal.
Tito Vilanova's assistant said Barca would need to get the balance right between going for goals and losing patience and leaving gaps at the back.
"We must find a balance between intensity, motivation and pressure but not make the mistake of rushing things," Roura said. "Two goals can come quickly, or they can take a long time to arrive. We must stay calm and not lose our heads."
Saturday's 2-0 Primera Liga win over Deportivo la Coruna was Barca's first clean sheet in 14 games, while Milan have scored at least once in each of their last nine games.
Holding the Serie A side scoreless at the Camp Nou was a big priority for his side, Roura said.
"Conceding goals is always a problem, and tomorrow it is practically an obligation not to concede," he said. "The game on Saturday against Depor was very important for us, for La Liga, but also to get positive feelings. I believe we achieved that."
Roura said Barca knew they would have to improve on their first-leg performance if they were going to progress.
"When you end up losing 2-0 you have not done something well, and Milan have done something well," he said. "They are a tough opponent, but the scoreline was harsh on us. Milan did not surprise me - I knew it would be difficult. Here they will try and keep the result as it is. We must know how to attack them."
With Xavi Hernandez expected to return from a hamstring problem to start in midfield, Barca's biggest pre-game selection decision looks to between David Villa, Alexis Sanchez and Cesc Fabregas for a place up front. Javier Mascherano and Adriano Correia are options at the back, but Carles Puyol and Dani Alves look more likely to start.
"We have been working with the side for the game for a few days," Roura said. "We still have a few things to decide, although we know the general idea. [Villa] has been very important for us in our last games. He can give us something different and has every chance to be in the starting XI."
Roura hinted, without confirming, that Barca had practised penalties this week, and said that the team could change shape mid-game if they needed to go for goals near the end.
"All options are open," he said. "We will see how things go. If we need to make a 'revolution' at some point, we will do it. We will decide depending on how we feel things are going."