He said: "I believe Fabregas is a different player to Kaka. Kaka is in this zone where he's not completely a striker and doesn't like to come deep and build the game up.
"And Fabregas is a complete midfielder, so they could play well together!"
Wenger added: "AC can be really average in the championship but can raise their game on big occasions. That's really surprising. They look invincible in Europe but beatable in Italy.
"If we pass the next round, then of course we'll believe we can do it, because we will have knocked out the holders.
"I believe we can knock AC Milan out."