The Italian side face a battle to reach the last 16 of the UEFA Champions League after suffering a 3-1 defeat to Borussia Dortmund on Tuesday.
While Pandev acknowledged the quality of Jurgen Klopp's team, he feels Napoli must have more faith in their own ability.
"We played against a great team and knew Dortmund were finalists last season," the forward told Sky Sport Italia.
"Now we have to look forward, keep working and hope it goes better in the next game.
"I don't know what we are missing, as we signed players with a lot of experience this summer.
"Maybe we need to be more determined and believe in ourselves more.
"We certainly need to have more belief, as we are a side with a lot of quality and can play at the highest level."
The Serie A outift need to either better Dortmund's result in Marseille or beat Arsenal by three goals in the final match of Group F to secure a place in the last 16 of this season's competition.
