Newcastle are at Anfield for the early kickoff on Saturday.
Klopp said, "They had a good start to the season and then they dropped off a little bit.
"They have found a system that works with five at the back. Wilson and Saint-Maximin - proper footballers. They have found their line up and we have a job to do.
"We have to offer a proper, proper fight tomorrow.
"We have to create, we have to score and we have to defend. We only have massively important games left. Six finals, and we have to win them all."
On team news, Klopp added: "Diogo Jota is fine, Nat Phillips is not back, Curtis Jones is back, all the others not.
"Do I know when Jordan Henderson is coming back? Not really. Not the next couple of weeks."