Jose Mourinho has said Manchester City might be a rich club that signs the best players but they "cannot buy class".
The Manchester United boss was responding to a question about City's Amazon Prime documentary, which aired this week.
"I think you can have a fantastic movie, respecting others," he told Sky Sports.
"You don't need to be disrespectful to have a fantastic movie.
"You can be a rich club and buy all the best players in the world but you cannot buy class."
Amazon's eight-part documentary of City's title-winning season lifts the lid on life in Pep Guardiola's dressing room.
The fly-on-the-wall documentary 'All or Nothing: Manchester City' gives a fascinating insight into the 2017-18 campaign.
An animated Guardiola is seen telling his players to "hate me" after drawing at Crystal Palace while his half-time team talk during the Carabao Cup final at Wembley is passionate.
Snippets of a touchline row with then Arsenal boss Arsene Wenger during that game are also shown, as is some footage of the tunnel fracas during City's shock FA Cup loss to Wigan.
Fabian Delph is also seen slamming the dressing room door after his sending off in the 1-0 fifth-round defeat at the DW Stadium.
However, Mourinho is clearly not a fan of the show and his comments will not go down well in the blue half of Manchester.
City host Huddersfield on Sunday, with United facing Brighton on the south coast later in the day.
United midfielder Andreas Pereira says he is relying on Mourinho to help him become a winner.
Pereira will be hoping to retain his place in the side after impressing in midfield against Leicester last Friday, when he ended an 897-day wait for a United appearance.
The 22-year-old spent time on loan at Granada and Valencia during that period - time away that has clearly benefited a player determined to kick on again and become a serial winner like manager Mourinho.
"We rely on him because he always prepares the team well," Pereira said of the Portuguese. "He knows what to do.
Nemanja Matic and captain Antonio Valencia returned to training on Thursday, but Mourinho says neither will be available for Brighton.
The United boss will also be without Marcos Rojo, Diogo Dalot, Ander Herrera and Sergio Romero as the side look to make amends for last season's loss at the Amex Stadium.
"It will be for sure a difficult game but we will try to prepare for it as best as we can," Pereira added.
"I think if you want to think about the title you have to think about every game and we have to win every game.
"Just in this week, so many people told me 'last year we lost against Brighton', so we have to prepare.
"I think we are going to get more prepared than last year because we know we lost last season, so this year we don't want to lose. We want to win over there."