The Nerazzurri coach believes that the two-time defending Serie A champions have now gone to another level after reinforcing their front-line
The Bianconeri are bidding for a third successive title and the Nerazzurri coach, who led Napoli to a distant second-placed finish last term, freely concedes that Antonio Conte's men will take some stopping now that they have added to their attacking options.
“[Tevez and Llorente] are two great players who will bolster an already excellent squad," Mazzarri told La Domenica Sportiva.
“Juventus were already strong, very strong. And now they've strengthened further. They're even more complete. They had a fantastic season last time out.
"They did well in the Champions League up to a certain point [the quarter-finals] and they'll be able to hold their own next year too.”
However, Mazzarri feels that his old club could again mount a credible title challenge.
“Napoli came second last season after four years of growth and I think they can only improve,” he reasoned.
“As a club they're in good shape and there's every chance of them succeeding.
"But Napoli is the past for me - I want to talk only about Inter now.”
Mazzarri spent four years in charge of Napoli before departing for Appiano Gentile this summer.