Barcelona expect AC Milan to go all out for victory at the Nou Camp with the Serie A side trailing 1-0 going into the return leg of their Champions League semi-final.
"They will come at us with everything," Barca midfielder Deco said of Wednesday's match.
"Their only chance of making the final is if they beat us in this game. They can't sit back and play on the counter-attack, they have to come forward and attack us."
The Portugal international believes that the Catalans will have to reproduce the sort of performance that helped them overcome Chelsea in the first knockout round if they are to oust the six-times European champions.
"It is like the Chelsea game," he said. "We had a one-goal advantage after the first leg, but it wasn't enough and we had to work even harder in the second match.
"We can't afford to take any risks at the start so that we avoid conceding a goal, but as the match goes on we will be able to open up and play our normal game."
Barca will be without the injured Lionel Messi and suspended fullback Oleguer, but Sweden striker Henrik Larsson is confident he has recovered from a thigh strain and will be available to provide cover up front.
Milan, who have not lost at the semi-final stage since being beaten by Real Madrid in the inaugural year of the competition in 1956, will be hoping to be more effective up front than in the first leg as they seek to claim a place in their 11th European Cup final.
The Italian giants will have Filippo Inzaghi back after the Italy striker missed last week's game because of a virus and with leading European Cup scorer Andriy Shevchenko and Brazilian forward Kaka likely to partner him in attack they are certain to pose a host of problems for the Barca back four.
"We believe we can get to the final," says coach Carlo Ancelotti. "Paradoxically losing 1-0 in the first leg will help us play with greater freedom and relaxation."
Milan, who lost to Liverpool in last year's final after squandering a 3-0 first-half lead, are bidding for their third final appearance in four seasons.
