Napoli go to Juve this weekend in good form under new coach Antonio Conte.
Manna told Radio Crc: "I hope to see a great match between two great teams. We are in a positive period, we have had three victories. It is part of a journey, the result of daily work.
"We are facing a team that is historically built to win, it is in their DNA. There is great enthusiasm, cohesion in the environment: we will find a strong team, that has just won well and deservedly is in the Champions League. We must be attentive, focused and work. We know that it is a stage of a journey.
"I saw Juventus' Champions League match, along with the other matches. Watching this tournament is difficult for us, because we are not happy about not participating. We are working to make sure this happens next year. Historically, Juve is built to win.
"We must be focused only on ourselves and work game after game. We know our objective and that we need time to get back to the top. We come from a complicated championship, but we have the conditions to compete with the others and try to get to the Champions League, as we have always said."