Marco Materazzi has taken a swipe at Real Madrid coach Rafael Benitez by claiming his former club Napoli "actually have a coach now".
Madrid president Florentino Perez gave his public support to Benitez in the wake of their 4-0 thrashing by Barcelona, despite mounting criticism of his brief spell at the club so far.
The ex-Liverpool manager's tactics have also been questioned by Napoli star Marek Hamsik this season, with the Stadio San Paolo side enjoying a strong run in Serie A under new head coach Maurizio Sarri.
And Materazzi, who played under Benitez at Inter, believes the 55-year-old has a history of upsetting the key players at his disposal.
"The main difference is that Napoli actually have a coach now," he told La Gazzetta dello Sport. "On Saturday I was watching El Clasico and I felt like Cristiano Ronaldo, Steven Gerrard, John Terry and Paolo Cannavaro - all players with a strong character who never got on with that one.
"At this moment, Napoli are frightening opponents. They are organised, all run for the team and have Gonzalo Higuain, one of the five best strikers in the world."
Napoli are just two points off Serie A leaders Inter after 13 games, with Fiorentina and Roma also in the frame, but Materazzi believes the Scudetto race is likely to be between the top two.
"Fiorentina and Roma are playing well, but I don't think the Viola can keep up that kind of tempo until May," he added. "The Giallorossi are a complete squad, but we have to see if the atmosphere surrounding them will let them chase the big prize.
"Juventus are already getting back into the title race, but I don't think they'll win it. AC Milan will enter the Europa League. Sinisa Mihajlovic is very good, but if you don't have quality in the squad, there isn't much you can do."