Jurgen Klopp slammed claims Jose Mourinho has made a poor start as Manchester United manager as "bulls***".
Klopp goes head-to-head with Mourinho at Anfield in the Premier League on Monday, with Liverpool fourth in the table, three points ahead of United.
But Klopp responded strongly to suggestions that United are underachieving, although they lost three straight games earlier in the season and spent heavily in the transfer window.
"Who says this?" the German said. "Four people in Liverpool? That's bulls***.
"[Mourinho] has started badly at United? He has won the first how many games? So now you are giving B grades for winning?
"He knows how successful football works. If you like it or don't like the way they play, why should he care? Why should he care?
"He has won the Champions League more often than I played in it. That is how it is. How can I say who is on the way up and who is on the way down? If we lose against Manchester United and we stand here, you ask me, 'What about you?'
"I'm not interested or part of the group that says Jose Mourinho was or has been a good manager."
Klopp insisted the result in Monday's game is more important to him than the style of football Liverpool use against United.
"The way to win it is not top of the list [of priorities]," he said. "It's not showing who plays the better football. We want to win this game.
"We don't just play to enjoy ourselves and say, 'Look it's nice'. We play to win. Of course I want to enjoy our games otherwise I have to wait for the result if there is nothing to enjoy during 90 minutes.
"There is not only one way. There are a lot of different ways and the most successful managers in world football had completely different ways.
"If you think [Pep] Guardiola, [Mauricio] Pochettino, Klopp all have the same way, right, but I know nothing about these guys that I could say is similar.
"From my point of view we have our way without looking left or right. We are only trying to do our best."