Liverpool manager is in no doubt about the quality of the Manchester United and England captain ahead of Premier League game at Anfield
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The England skipper has lost his place in the starting XI for club and country going into Monday's huge Premier League clash with Liverpool at Anfield on Monday.
Klopp, though, has no doubt Rooney remains a potent force despite a run of only one goal in 13 matches across all competitions this season.
"Wayne Rooney is a goalscorer and a threat," Klopp said at his pre-match media conference.
"A situation like this can happen in a long career. From my side he's a world-class player.
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"But I am manager of Liverpool so I know it is not allowed to like United players!"
Klopp also talked up the threat of United and believes the signings of Zlatan Ibrahimovic and Paul Pogba ensures they are significantly stronger than last season.
United secured a Premier League double in the first of four meetings between the two sides in 2015-16, only for Liverpool to get revenge over two legs in the Europa League.
Klopp added: "Ibrahimovic was not there, Pogba - they are both world-class players and when they are in your team they are not worse than last year, for sure.
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"Unfortunately this is a really strong side from Manchester, they know about football, they are experienced, cool in the right moments, they don't need world-class performances to win a game.
"Even on rainy days, it's possible to score and win - they have those types in the team, but it doesn't mean they will win the game. It just means they have a chance."
The German, who was named Premier League Manager of the Month for September earlier on Friday, acknowledged the magnitude of clashes between Liverpool and United.
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Klopp continued: "Very intense game, two good sides. They have big quality and we have to respect this, as we do.
"But this is Anfield. We have to show this. We have had a few nice atmospheres but I'm open for the best atmosphere.
"We need everybody in a Liverpool shirt in this game. Apart from the table, it's a very important game. I know about the history, I like the special stories. The whole world will watch this game, it's a big honour to be part of it.
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"The whole world will watch Liverpool versus Manchester United. It's up to us to perform at our best!
"As long as I live Liverpool against United will never be just a normal game. You cannot and should not ignore the special circumstance of a game like this. You have to be ready."
Klopp is hoping Adam Lallana (groin) and Georginio Wijnaldum (hamstring) will be passed fit to play, as well as defensive duo Nathaniel Clyne (knee) and Dejan Lovren (groin).