The Nerazzurri must overturn a one-goal deficit to avoid crashing out of the competition after a 1-0 defeat at the Velodrome in the first leg of their Round of 16 tie.
Despite the rivalry between the two clubs based in the city of Milan, Allegri stated that he will cheer for Inter during the match as Claudio Ranieri's side are representing Italy overseas.
"Inter have a great chance of going through and everyone in Italy should cheer for them," Allegri told Sky Sport Italia.
"In European competitions, we need to root for the Italian teams and that is what I will do tomorrow."
Milan are already through to the quarter-finals of the competition after a 4-3 aggregate victory against Arsenal.
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