Vieri can see all his former clubs being involved in the Scudetto race.
He told Quotidiano Sportivo: "The first matches are difficult because you have little time to train, especially after the summers with the big tournaments.
"It's not even easy to play in such heat. Inter and Juventus have done well, Milan is still a bit behind. Napoli themselves started badly and then got two victories.
"I predict an entertaining championship until the end. On the third day they all have time to recover."