Jose Mourinho believes Manchester City's players go down very easily, with the Manchester United boss saying it only takes a "little bit of wind" to knock them over.
The 175th Manchester derby is comfortably the biggest match of the Premier League season so far as second-place United attempt to claw back Pep Guardiola's runaway leaders.
Eight points is the gap ahead of Sunday's mouth-watering Old Trafford encounter and Mourinho has looked to disrupt rivals City before a ball is kicked.
While full of praise for Guardiola's side, the Portuguese used the opportunity to underline the unbeaten league leaders' apparent tendency to go to the deck.
"They are a good team," Mourinho said. "They defend well, they react well to the moment they lose the ball.
"They have a good dynamic in attack, they have creative movement.
"They have amazing players, they have a fantastic coach, they have lots of good things.
"If you ask me one thing that I don't like a lot it's that they lose their balance very easily.
"You know, a little bit of wind and they fall."
Mourinho's comments are unlikely to go down well at the Etihad Stadium, especially after Arsenal boss Arsene Wenger accused in-form Raheem Sterling of diving last month.
Fernandinho was booked for simulation at Huddersfield and Burnley boss Sean Dyche fumed with the way Bernardo Silva went down to win a penalty earlier in the campaign.
Mourinho has only added fuel to that particular fire, while the United boss has suggested he would find himself in hot water if he expressed political views in the way Guardiola does.
The City boss wears a yellow ribbon in support of imprisoned Catalan politicians.
"If the rules allow us to do that, he is a free citizen to do it," Mourinho said.
"But I am not sure if the rules allows to have any political message on the pitch. That's just my doubt.
Read More
"But I know Pep and I know his feelings like everybody else knows because it is public about his country."
Asked if he would never do a similar thing, he added: "I think I wouldn't be allowed to do. That's just what I think."
UEFA allow political messages without offensive content, while the Football Association is understood to have a similar criteria.
The subject kicked off a pre-match press conference in which Mourinho pledged to stop taking aim at his own fans.
The United boss was put out by an apparent lack of support for Romelu Lukaku in October's when against Tottenham, when he held a finger to his lips and told the doubters to calm down.
Mourinho then made a chatting gesture at the following home game against Benfica having dug out some of his own fans in his programme notes, leading the Manchester United Supporters Trust to invite him to "discuss his concerns" around the Old Trafford atmosphere.
"I stop with that," he said. "I am not going to write any more words about it, I am not going to say any more words about it.
"We are paid to work and to work hard and to give the best we can, not to criticise fans and I am not going to say any words.
"Because it is the reality of things. I am not paid to come here and to make any comments or to ask for something from the fans.
"I am paid to try and give them happiness, which is what I try to do every day."