Zambrotta played alongside Messi for two years at the Nou Camp.
"There are different players and tactical systems, but both teams constantly look for entertaining football above all else," he told Tuttosport.
"This is why Ronaldinho, when fielded in a similar position to the one he had at Barcelona, is returning to his best.
"Who is Milan's Messi? That's easy - Pato. We know how much he's worth and what he can do. Pato can become as good as the Argentine.
"I have also been very impressed with Thiago Silva, as with Alessandro Nesta he forges a very strong defensive partnership."