The Partenopei boss says his team will face a tough task in one of the most challenging draws of the Champions League, where his side will face Arsenal, Marseille and Dortmund
The Serie A side were drawn alongside Premier League giants Arsenal, last season's finalists Borussia Dortmund and Olympique Marseille in the competition's Group F on Thursday.
"When you talk about the Champions League, all the groups are difficult," the 53-year-old told reporters.
"Our group seems one of the most balanced, certainly not easy, as all the clubs we're facing have experience in the Champions League. I think it will certainly be a great challenge for us.
"Borussia Dortmund are a top level side who were finalists last season and play good football.
"We know Arsenal well and played them not long ago in London for the Emirates Cup. They have an excellent coach and experience on the international scene.
"I had my first European success in Marseille, the Uefa Cup final with Valencia. It won’t be easy there, as the stadium is a fiery atmosphere."