The Premier League giants begin the defence of their European title at the Stadio San Paolo, where they were beaten in October last year.
Reflecting on that 1-0 defeat, Klopp said Liverpool's failure to adjust tactically was the reason for their loss in Naples.
"We talk a lot about intensity. The Napoli game last season was not intensity, Napoli was an organisation problem," the Liverpool manager told UK newspapers.
"All the things we tell the boys, it is all about intensity and how much we have to invest, but before that it is all about information. What do you have to do in these moments?
"And Napoli play a specific style. To make it very simple, we played against them in our defending like they had one number six but they had two number sixes, the cheeky b*******. We knew before.
"We told them they had two number sixes but then everyone came too late. We tried to change it in the game and nobody listened and nobody could change and in the end, we were lucky it was only 1-0. It was really this kind of off day."
The loss to Napoli was one of three away defeats Liverpool suffered in the group stage last season, although they improved on the road on their way to the title.
Despite being the defending champions, Klopp said his side were underdogs heading into the clash.
"We will have to invest whatever we have in the game and then we have a chance but we don't go there as a favourite," he said.
"Yes, we won the competition last season but it is difficult against the runner-up in Italy for the last few seasons, who is really close to Juventus this year and a really strong team.
"They are different to last year, not too much, but enough to have a view on it."