Liverpool boss Jurgen Klopp says the Anfield club would not be allowed to play like Manchester United after their goalless draw at Anfield on Saturday.
Liverpool dominated for long spells but could not break United down, and Klopp said: "I'm sure if we played like this, you could not do this at Liverpool. Obviously for United it is OK."
Manchester United boss Jose Mourinho said he lacked attacking options.
"I needed my bench, and I didn't have a bench," said the Portuguese.
In a BBC Sport poll, 69% of voters thought that Manchester United were too defensive against Liverpool.
Liverpool managed a first clean sheet in eight games yet were left frustrated by United at Anfield for the second successive season.
They peppered United, who enjoyed just 38% of possession, with 20 shots but could not find a way past the brilliant David de Gea, who denied Joel Matip with a magnificent reflex save from close range.
Liverpool have now won just once in eight matches in all competitions and have drawn the last three games as they struggle to repeat their goalscoring feats of last season.
In contrast, United have been finding the net more freely this season compared to last, with Romelu Lukaku to the fore - but the Belgium striker was a peripheral figure up front and the visitors' gameplan was built on containment.
- Listen: 'Mourinho not looking at this as a one off game'
- Wasteful Liverpool frustrated by United
- Reaction from Anfield stalemate
'United came for a draw'
Klopp believes his side was unlucky not to beat their fierce rivals in what was another much hyped but ultimately low-key game between two of the most successful clubs in English football.
"It's quite difficult when a top-class team like United has that defensive approach," said the German.
"I think United came here for the point and they got it. We wanted three points and didn't get it.
"We were dominant, it is a home game for us so we should be dominant. I am okay with the performance - it is not my job to judge the United performance.
"For me today, one team who can become champion this year was in our stadium and is not a world apart from us.
"It's not that we are playing different planets and they are really good and we do not find the entrance to the stadium."
'Game of chess'
Mourinho described the second half as a game of chess and defended Manchester United's tactics when asked about his side's modest attacking ambition.
The United boss, who did not start England striker Marcus Rashford as a result of a knock, said United came with the aim of three points "but my opponent didn't open the door for me to win the game".
"I was waiting for Jurgen to change, I was waiting for him to go more attacking but he kept the three strong midfielders all the time where he was having control because I only had Ander Herrera and Nemanja Matic.
"When I brought on Jesse Lingard and Rashford I was waiting for him to bring on Daniel Sturridge or Dominic Solanke.
"But he decided to change player by player and kept the strong midfield.
"That midfield today was stronger than my midfielder."
'Chess not much of a spectator sport'
Analysis by BBC Sport's Simon Stone
What may have looked to me - and virtually any other observer - as a tepid goalless draw between two of England's heavyweights, actually left both men in charge relatively happy.
Jurgen Klopp said Liverpool's performance was "not too bad".
His evidence was the absence of his creative sparks Sadio Mane and Adam Lallana, the knowledge Liverpool would have gone 10 points behind Manchester United after just eight games had they lost and the fact David de Gea made the game's outstanding save.
It felt as if Klopp decided before kick off that "Manchester United will not lose many games", so set his team up to be solid, restrict the visitors and go from there.
Jose Mourinho was ready for that but, with Marouane Fellaini absent, he needed Klopp to make an offensive change for his speedy substitutes to make a difference.
The change never came. Liverpool stuck to Plan A. If either side had a Plan B, neither reverted to it and the game ground to a goalless conclusion for the second season running.
"They are are happy, we are not happy," said Klopp, before explaining that he was reasonably happy after all.
Liverpool remain where they were, on the fringes of, but not among, the title contenders.
As for those watching from the stands or on TV, Mourinho described the second half as "a game of chess".
And, as everyone knows, chess is not much of a spectator sport.