Rui Costa, who is now Benfica sporting director, said that he has been impressed by Viola's start and that they could yet mount a title challenge.
"I always follow and pay attention to the Italian league," Rui Costa told reporters. "Juventus aren't repeating the path of past seasons, but I think they're still the favourites.
"Roma are a sweet surprise and you find that they have great merits.
"I really like the game of Fiorentina, and not just because of how they played the game on Sunday against Juventus. I hope they can make their way up the table and fight for the Scudetto."
Rui Costa played for Fiorentina between 1994 and 2001.