The Spanish giants go into the second-leg of their last 16 showdown with AC Milan trailing 2-0 after suffering a shock defeat in the San Siro.
This leaves them needing a massive victory to stay in the competition but the midfielder insists it isn't beyond Barca.
He said: "We will make it through to the next round.
"I would put my hand in the fire as many times as I had to for my team. I have absolute confidence that we can do it.
"It will be difficult but not impossible. We have to play this match as if it was a final. That's what our mentality needs to be from the first minute to the last."
Fellow midfielder Xavi added: "We still have 90 minutes, maybe even 120 minutes. A lot can happen in a match.
"We need to be careful, we can't lose possession, we need to avoid giving them any opportunities to counter-attack, we can't commit stupid fouls and our attacks need to have purpose."
Meanwhile, AC Milan vice-president Adriano Galliani hopes Barcelona's "monster" – Argentine superstar Lionel Messi – has a night off.
He said: "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 tonight.
"One thing is certain – it will be another great challenge, an infinitely difficult challenge. We will be going into an incredibly heated atmosphere."