The Reds will take on their Portuguese opponents at Anfield with a 5-0 advantage following their emphatic win in the first leg of their last-16 tie.
United have the chance to regain second place with a win over Crystal Palace tonight. But should they do so, Liverpool will be able to regain that position with a win at Old Trafford on Saturday. However, Klopp insists he won't be saving any players for the match by giving them a night off on Tuesday.
He said: "It's not about rest. Porto have won all their games since we played them.
"They will strike back, that's what they want. They are Portuguese and proud and will give a fight.
"If anybody here thinks they come here and give the game up, leave their star players at home or whatever they are mistaken. It's Champions League and the whole world is watching.
"I don't think for a second about resting anybody. I know it's Manchester United afterwards but we cannot change it."