Napoli coach Rafael Benitez said his side have the belief they can overcome the challenge of a "massive" game against Arsenal on Wednesday to book their place in the last 16 of the Champions League.
Napoli take to their San Paolo pitch sitting third in Group F three points behind the English Premier League leaders but on the same points as second-placed Borussia Dortmund, who are away to pointless French side Marseille.
It has thrown up a variety of scenarios, even the possibility that even if they beat the Gunners, they may still finish third and drop to the Europa League.
In the event Dortmund beat Marseille, Napoli need to beat Arsenal by three clear goals to qualify for the knockout phase, but Benitez said the Serie A title challengers are confident.
"Everyone is saying we have an impossible task, but we believe. The team has trained at 100 percent and given it everything."
Benitez has broken with habit and kept the players under lock and key at their retreat in Castel Volturno in a bid to "talk, focus and train well tomorrow morning."
He added: "The players are very motivated. For us it's very important, we've done well so far in the Champions League and we are happy to be involved in the campaign.
"We're proud to have got where we are, games like this against Arsenal are decisive but it's better to be playing them than watching them on television. It's a massive game for us."
While Arsenal need only a draw to go through, Napoli need to beat the Gunners to have any chance of securing a runner-up spot which Dortmund could hold on to with victory in France.
If both Napoli and Dortmund win, all three teams would finish on 12 points and the standings would be decided by head-to-head clashes and goal difference.
If, however, Marseille upset the form book and beat Dortmund a draw would be enough for Napoli to secure the runner-up spot and follow Arsenal into the knockout phase.
Napoli will be without offensive midfielder Marek Hamsik, who is still recovering from injury, and are likely to call on number two 'keeper Rafael as Pepe Reina, who is suffering from a muscle injury, is still sore after training.
"We'll see how he is tomorrow and decide," said Benitez.