The ex-Portugal star is optimistic about the Camp Nou side's chances at qualification for the next round, and he believes Victor Valdes' suspension is too heavy.
The Blaugrana were beaten 2-0 at the San Siro in last month's opening leg, but Baia has little doubt that they will eventually emerge victorious once the home tie is complete.
"Knowing the players, the fans and the club's history, I am confident that Barcelona have what it takes to pull off a historical comeback against Milan," Baia told La Xarxa.
The former Portugal goalkeeper also had his say on Victor Valdes' four-match ban following his dismissal against Real Madrid, and he feels the punishment is rather harsh.
"Valdes' four-game suspension is a very severe punishment," Baia said. "It's a lot of games for a player who pretty much has a clean sheet when it comes to this kind of behavior.
"It can be difficult to keep your emotions in check when you think an injustice has happened, and that's how Victor must have felt."
Valdes will miss the Primera Division games against Deportivo La Coruna, Rayo Vallecano, Celta Vigo and Real Mallorca due to his ban, paving the way for Jose Manuel Pinto to feature in goal.