Defeats by City last September, Chelsea at Stamford Bridge and the recent 3-0 home loss to old rivals Liverpool have taken their toll on the United manager.
A 1-0 win over Arsenal on 10 November is their only victory against a top-nine side in the league under Moyes but United will get the chance to improve on that poor record at Old Trafford.
"They have definitely hurt," Moyes said of the high-profile defeats.
"They have hurt more because I joined Manchester United with big expectations myself, that I was coming to the winning football club.
"I've got a winning mentality and that's what I wanted to do, so I'm disappointed with myself and I'm disappointed that we've been unable to do that.
"But it has not been for the want of trying, that's for sure.
"We want to try and perform better in the bigger games than what we have done."
City boss Manuel Pellegrini has adopted a conciliatory tone ahead of the derby, in contrast to comments made last month, where he suggested United were a spent force and that City were the only team in Manchester.
Moyes has taken issue with that assertion though and hit back at his counterpart.
Moyes says United's players are determined to reward the club's fans for their loyal support with a big performance in the derby.
I've said many times how well the supporters have reacted to what has been a difficult season," said Moyes. "They have been great and the atmosphere has been great inside Old Trafford.
"They have played their part in helping the team. We've not always done our side of it, but recently we have, and the supporters have responded to that as well.
"We go out to win every game, not just the derby game, but obviously it means a lot more to supporters and it means a lot in the city, if we win."
Wayne Rooney will be a key player for United against City and Moyes insists the striker should already be regarded as a club legend, having scored 212 goals for the Red Devils.
"If you are third top scorer of a club like Manchester United you already are a legend," said Moyes.
"As long as he doesn't pick up any serious injuries he has a real good chance of breaking Denis Law's and Sir Bobby Charlton's records and that would be some feat.
"His form throughout the season has been very good and his goal against West Ham capped it all off. He showed what he is about and he has a big energy back again."
"Manchester United had lots and lots of seasons of domination," added the Scotsman.
"I don't think if I was a manager I would have turned round and necessarily said that we were the only club in Manchester because football does change, it goes in cycles."
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