AC Milan boss Allegri rates Lazio clash ahead of Barcelona
"Friday's game will be tough because it is our first match for 20 days if we ignore the Como friendly.
"Fortunately our physical and mental condition is good, a few of our internationals got a game this week and this is a good thing.
"You have to be ready mentally to play this type of game. Lazio will be fighting for the championship this season.
"They have strengthened and have been playing as a team for a year - even if they now have Cissè and Klose in attack.
"They'll play an open game and I don't think they'll play as deep as they did a year ago. It will be a great game."