Roberto Mancini said too many teams are afraid of Manchester United to play well against them.
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The Manchester City manager believes Sir Alex Ferguson's team get easy victories because some of their opponents do not believe they can defeat the league leaders.
And he questioned the mentality of most of the teams who face United, calling them "soft".
Mancini was frustrated that Sunderland, who beat City at the Stadium of Light in December, put up less of a fight against United last week.
"No one plays well against United because they only play with fear," he said.
"Every team that plays against United plays very soft because they think this game is difficult, they can't beat them. If you play strong against United, you can beat them, like you can beat us."
United have only dropped points against four clubs this season, with Tottenham winning at Old Trafford and drawing at White Hart Lane, Everton and Norwich recording home victories and Swansea holding the league leaders at the Liberty Stadium.
Mancini said he was not accusing other teams of lacking effort, explaining: "I don't think they don't play [at] 100% but their mentality is poor in that game. They think they can do nothing but I don't think that is true. If you play with mentality, in football you can beat every team."
However, he does believe that United's two decades of dominance have given them a psychological edge and even though City are the defending champions, he feels they approach games against his team in a different way.
"We don't have the same importance like United at this moment," he added. "Maybe in 10 years, it will be the same. The history is very important."
City visit Old Trafford on Monday, returning to the scene of a 6-1 win last season, with Mancini insisting there will not be a repeat but confident his side can take three points.
He said: "The 6-1 is in history. We can talk about this for another 200 years but it is impossible to do this result another time but I think we know we can beat them because they are not better than us."