Manchester United boss Jose Mourinho has accused Manchester City of a lack of class following the release of their 'All or Nothing' documentary series.
The style of Mourinho's side was portrayed as negative in an episode that featured the Manchester derby on December 10 of last year, narrator Ben Kingsley billing it as "possession versus defence; attacking football versus park-the-bus".
City's 2-1 victory at Old Trafford was marred by a clash between players in the tunnel and the Portuguese manager criticising Pep Guardiola's team for celebrating excessively.
Mourinho has again hit out at the Premier League champions, expressing his displeasure at a show he sees as "disrespectful".
"You can have a fantastic movie while respecting others. You don't need to be disrespectful to have a fantastic movie," he told Sky Sports.
"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."
United finished as runners-up to City last term and Mourinho feels it will be difficult for the Red Devils to improve due to the strengthening of their top-six rivals.
"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 £200million, 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."