Boss Rudi Garcia admits Napoli must beat Union Berlin to ensure they maintain a strong position in the Champions League.
Garcia’s men sit second in Group C, three points behind leaders Real Madrid, who won 3-2 in Naples earlier this month.
Napoli opened their campaign with a 2-1 win over Braga in Portugal and now go to Union Berlin on Tuesday.
“We know all about Union Berlin’s recent history, they reached the Champions League after an excellent season last year,” said Garcia.
“They have strong players like (Leonardo) Bonucci and (Lucas) Tousart. The Champions League is a great competition to play for both players and coaches.
“We started well, but then we didn’t take any points against Real Madrid and we have to win tomorrow.”
The Serie A champions ended a run of successive home defeats by Real in Europe and Fiorentina in the league with a 3-1 win at Verona on Saturday in which Khvicha Kvaratskhelia scored twice.
However, they will once again be without star striker Victor Osimhen as he continues his recovery from a hamstring injury.
Berlin coach Urs Fischer has told his Champions League debutants to have “fun” as they attempt to end a dreadful run of eight successive defeats in all competitions.
Fischer told a press conference: “We have a difficult opponent ahead of us, the Italian champions, but we must remain optimistic and remember that football is fun.
“We will face Napoli in the right manner to try to take away points.”
That is something the Germans, who finished fourth in the Bundesliga last season, have failed to do in either of their games to date after losing 1-0 at Bernabeu Stadium courtesy of Jude Bellingham’s stoppage-time strike before going down 3-2 to Braga at the Olympiastadion in a game in which they had led 2-0.
They have suffered on the domestic front too after going into the international break on the back of a 4-2 defeat at Borussia Dortmund and emerging from it to lose 3-0 at home to Stuttgart on Saturday.
However, midfielder Rani Khedira, who made his first league start of the season at the weekend after injury, insisted he and his team-mates had to remain optimistic.
Khedira said: “The key is to continue to have confidence and optimism. Tomorrow we will have to play with humility, and it will not be easy, but we must not get down about it and we must try to win.”
Germany international Robin Gosens is a doubt for the game, while much-decorated Italy defender Leonardo Bonucci will hope for a return after failing to make it off the bench at the weekend.