The Reds will face Eduardo Berizzo's side for the first time since their painful 3-1 defeat in the final of the Europa League 16 months ago in Basel.
Los Rojiblancos arrive at Anfield tonight in good form, having taken seven points from their opening three La Liga fixtures, but Klopp has warned them to expect to come up against a much-improved Liverpool side this time around.
"I think we have proved it already we are stronger than we were in the final," he is quoted as saying by the Liverpool Echo. "At the time it was a terrible defeat but we took a big step. We have changed a lot of things since the final, but it is always this way and they have made progress too.
"Last season was another very successful season for them so it is a really interesting challenge for us. For me, the most important thing is this is a proper Champions League game and nothing else, not Europa League, not a final from two years ago, it is real Champions League.
"I know when the draw was made people were saying we are lucky with the group, but then you watch Sevilla and analyse them and think: 'Oh my God, that's real football'. A good mixture of technical skills, good match plans, different match plans, this mixture of being cool, being good footballers and being ugly – how Spanish teams are.
"They are not shy in challenges and things like this. This is a real challenge for us, but we want to be there so much and now we have to show what we are."
The Reds' group also includes Maribor and Spartak Moscow.