The Bianconeri face Spezia at the Stadio Picco today at 17.30 UK time.
They are still without a victory in Serie A so far, but have won against Malmo in the Champions League.
Next week, they’ll host title holders Chelsea at the Allianz Stadium.
“Chelsea should not take anything for granted,” Zola told La Gazzetta dello Sport.
“Tuchel is an intelligent coach and Chelsea are a top team. The game against Tottenham was impressive. There’s a lot of quality there. They withstood the impact of Spurs in the first half and won the game in the second half, by scoring three goals.
Zola: "Osimhen devastante, è l'erede di Lukaku. Scudetto al Napoli, perché no?" https://t.co/QLCPzuNfRW
— La Gazzetta dello Sport (@Gazzetta_it) September 22, 2021
“However, Juventus never die, the first half against Milan was good. They can make up lost ground in Serie A.”
The Bianconeri are 10 points behind Napoli. The Partenopei have won their opening four league games of the season and can jump to the top of the table if they beat Sampdoria on Thursday.
“Napoli are really strong in every department,” Zola, a former Partenopei striker, said.
“They have Osimhen, Insigne and Politano up front, they quality in midfield, a solid defence with Kalidou Koulibaly and two reliable goalkeepers. I can’t see weak points in their team.
“I didn’t know Osimhen when he arrived last year, but I’ve studied him a little and I’ve discovered a talented player.
“His movements are so good and his athletic strength can be devastating. He is Lukaku’s heir, he is still young and with room for improvement.”
Osimhen, 22, joined Napoli from Lille in the summer of 2020.
He scored ten goals in 30 appearances with Napoli in his first season at the club.
He has three goals in four appearances so far this season and his contract at the Stadio Maradona expires in June 2025.
Zola scored 36 goals in 136 appearances with Napoli between 1989 and 1993.
He then joined Parma and Chelsea before returning to Cagliari where he ended his career in 2005.