Manchester United are an exceptional team and their midweek comeback win over Atalanta in the Champions League showed they have the quality to cause any team problems, Liverpool boss Juergen Klopp said on Friday.
United were 2-0 down to the Italian side at Old Trafford before mounting a spirited second-half comeback to win 3-2 and move to the top of their group.
Former United midfielder and television pundit Paul Scholes suggested Klopp, whose side visit Old Trafford on Sunday, may have been "rubbing his hands together" at halftime after watching their first-half performance, but the German manager said that was not the case.
"I wasn't rubbing my hands watching that game, there was no reason for it. Atalanta caused United some problems but even in the first half, United had three clear-cut chances," Klopp told reporters.
"The second half was a pure power presentation of United going for it. With the quality they have, they can cause any team problems.
"I prepare the team for a tough game against an exceptional, really good opponent... We are long enough together to know we're up against a really good team and it's an away game as well for us."
United are winless in their last three league games, losing twice to drop down to sixth. Klopp said they would be hurting ahead of one of the marquee fixtures of the season.
"We all know how the world in football is. United-Liverpool is a massive game," Klopp added.
"I think they aren't overly happy with the results they've got so far, but we all know that they are able to do incredible stuff. That's how it is, we saw it already."
The match will feature a highly-anticipated meeting between United's Cristiano Ronaldo and Liverpool's Mohamed Salah, but Klopp said there was no point trying to compare the two players.
"Why should you compare Cristiano and Salah? Both are world class players," he said.
"I would say Mo's left foot is probably better and maybe Cristiano in the air is better and with his right foot. Speed-wise, both are quick and they're both desperate to score goals."
Klopp said midfielder Curtis Jones had returned to training and could be in contention to play but Thiago Alcantara has still not fully recovered from a calf problem.
(Reporting by Rohith Nair in Bengaluru; Editing by Toby Davis)