Jose Mourinho has accused Manchester City of a lack of class after the airing of their behind-the-scenes documentary 'All or Nothing'.
A film crew followed Pep Guardiola's side as they won the Premier League title with a record points tally in the 2017/18 season.
The eight-part series was released on Friday, showing clips from inside the dressing room, the boardroom and on the training ground.
The second episode features City's win at Old Trafford in December, with the narration saying: "It is Guardiola versus Mourinho once more; possession versus defence; attacking football versus 'park-the-bus'".
The same episode later shows City fans chanting 'park the bus', intercut with clips of Mourinho in his post-match press conference, dismissively responding to questions about possession statistics.
Asked about the publicity surrounding the documentary, Mourinho told Sky Sports: "You can have a fantastic movie while respecting others.
Live Renault Super Sunday
"You don't need to be disrespectful to have a fantastic movie. You can be a rich club and buy the best players in the world but you cannot buy class and they showed that clearly, that was really obvious."
After finishing second last season, United will be looking to topple City this year.
But Mourinho is expecting a tough campaign, especially as several top-six rivals have strengthened over the summer.
"Last season, we put ourselves in a difficult position, because to do better we can only finish first," said Mourinho.
"When I read sometimes and watch sometimes, it looks like we finished sixth or seventh and everybody did better than us. We finished second.
"Liverpool are trying to win the title with their amazing investment. Chelsea have a fantastic squad, Manchester City have a fantastic squad too, Tottenham made an incredible investment by keeping their players, that's the best investment you can make.
"They could be spending £200m but if they lose Harry Kane or Christian Eriksen... the biggest investment was keeping all their best players. Arsenal will be better even though they lost their first match.
"I think it's going to be a very hard season."
Read the full exclusive interview with Jose Mourinho on Sunday morning ahead of Brighton v Manchester United on Sky Sports