Juventus will also beat Salerentina easily. But this is Copa Italia and weak teams beat strong teams here frequently. So anything might happen.
Salernitana may not be a team that is equal to Juventus. However, a few weeks ago, Salernitana was able to hold AC Milan to a draw which was experiencing inconsistency. Even though this could be considered a coincidence, at least this could be a sign for Juventus to remain careful from attacks by Salernitana players. However, Salernitana chances of winning the match, remain very low.
Considering that the match will be held at Juventus venue, this of course adds to Allegri squad motivation to advance to the quarter finals. There isn't much that can be said about Filippo Inzaghi current squad, their chances of winning are very low as is their current position in the Serie A standings.
I think Juventus is one of the favorite teams in the Coppa Italia, as well as in Serie A. Allegri is able to make the club appear consistent, even though the challenges he faces are very different from other teams, I mean like in the case of Pogba and Fagioli.