As seven-time winners, Milan have become synonymous with Europe's premier club competition.
But their qualification for this season's group stages hangs firmly in the balance following their 1-1 draw in the first leg of their play-off against Dutch outfit PSV Eindhoven.
"We know how important the game is," Allegri said.
"We will be facing a team that plays good football. They have a young squad and they play very well.
"They created some difficulties for us in Eindhoven, but our performance was good back then and we need to repeat it tomorrow."
Milan midfielder Riccardo Montolivo said the team was 'angry' after their showing against Verona, and are determined to bounce back in the best possible fashion.
"We've been talking about the game against Verona from the moment it was over, because we were disappointed and angry with ourselves," he said.
"We put in a poor performance, so we are really eager to show that we are not the same side who went onto the pitch, and performed so miserably last Saturday in Verona."
