Messi talks Milan, Real and Vilanova
The Catalans have lost three of their last four games, including two defeats to Real Madrid, but their No10 is confident they can regain their best form when they need it most against the Italians on Tuesday.
"It is obvious that we have to do a little more," said Messi. "Lately we have come from a run of defeats and we are aware of what we need to do to change that.
"There is a key game coming up for us to react and make this change. To come back is what we all want.
"We know it will be very difficult, but we believe it's possible. If they can do it there, then we can do it here. We know that if they score a goal it will be more difficult and that Milan have very good players, but we will have our chances."
Messi also acknowledged that the ongoing absence of coach Tito Vilanova as he undergoes cancer treatment in New York has impacted on the squad, but refused to blame the loss of the 44-year-old as a reason for their recent dip in form.
The Argentina international said: "It has affected us a lot and I think it has taken its toll when it comes to preparing for each competition, but we have a strong dressing room and I don't think we can put the blame on this situation."
Messi labels Real 'candidates' to rule Europe
Messi also reflected on Real Madrid's 2-1 win over Manchester United at Old Trafford on Tuesday night, and admitted that Los Merengues are now a serious candidate to win the Champions League.
"Madrid are demonstrating that they are very strong," he said. "They knocked us out of the Copa Del Rey and they are now in the quarters of the Champions League. They are candidates to win the Champions League, just as United were."