The ex-Bianconeri boss thinks the €63 million received for Edinson Cavani can acquire some quality players, while praising "perfect" Carlos Tevez
The Partenopei finished second in Serie A, nine points behind Juve, in 2012-13 but are without coach Walter Mazzarri (Inter) and top goalscorer Cavani (Paris Saint-Germain) heading into the new campaign.
However, the legendary former trainer of the Bianconeri, does not believe Rafa Benitez's side are going to suffer from the loss of the Uruguayan and also tipped AC Milan to challenge the reigning Scudetto winners.
"Napoli hold the treasure in their hands after Cavani sale - €63 million is a frightening figure," Lippi told La Gazetta dello Sport. "If club president Aurelio De Laurentiis finds the right players, they can quickly become a credible rival.
"Do you remember what happened when Juve gave Zinedine Zidane to Real Madrid? I still remember the call from the chiefs: 'Marcello, we have to give bad news - Zidane's going to Real.'
"It was a punch in the stomach. But the money brought in from Zizou's sale secured Juve signings such as [Gianluigi] Buffon, [Fabio] Cannavaro and [Lilian] Thuram and opened a new, extraordinary cycle.
"The story can be repeated with the sale of Cavani. Do not forget that Napoli has a born winner on the bench in new coach Rafa Benitez.
"Milan are another team that can come out from the group to challenge. Stephan El Shaarawy was and remains a champion.
"After being out of this world for the first half of the season, he is back on Earth. He needed to take a breather. There's no mystery behind his little crisis. He can easily coexist with Mario Balotelli."
Lippi is evidently a huge fan of Juve's signing of striker Carlos Tevez from Manchester City this summer, though he also took time to praise the progress of last year's transfer coup Paul Pogba.
"Tevez is a perfect investment. He's a warrior, a fighter, he has that nastiness that brings positive electricity in a team," the World Cup-winning coach added. "Juve did not have a player like that.
"And then there's Paul Pogba. He has class, strength, sense of play. He can use his feet and his head. "