The experienced midfielder believes that a number of remarkable comebacks in the past are proof that anything can happen on Wednesday
The Serie A champions were beaten 2-0 by FCB at the Allianz Arena last week, yet Pirlo remains optimistic about his side's chances of making it to the semi-finals of the competition.
"We have to believe in ourselves and be convinced that we can turn things around," the influential midfielder told Tuttosport.
"I was there in Istanbul and La Coruna, I learned the hard way that everything's possible.
"In Istanbul, Milan were leading 3-0 against Liverpool and we were convinced we would win the Champions League. The game finished 3-3, though, and we lost after penalties.
"And then there's the tie against Deportivo La Coruna. After the 4-1 win at San Siro, we lost the away game 4-0. And we were Milan, not just any other team..."
Wednesday's return at Juventus Stadium is scheduled to kick off at 20:45CET.