The Red Devils boss suggested there would be an "inquiry in the House of Commons" if his side got as many penalties as their neighbours, who he admits are their "biggest threat"
Roberto Mancini's side have been given 21 penalties since the start of 2010-11 – including four in their last three home games, United have been awarded the exact same amount in the time period.
Despite that fact, Sir Alex believes his side would likely be lambasted for influencing officials were they to receive such good fortune with key decisions.
"The number of penalty kicks they get - 21 in the last year or something like that," he told reporters.
"If we got that number of penalty kicks there'd be an inquiry in the House of Commons. There'd be a protest."
Sir Alex also went on to admit that the Manchester derby has now overtaken games against Liverpool as the biggest landmark on the United calendar.
|MIND GAMES WORK AGAIN|
|7/1||Manchester United are 7/1 with bet365 to score a penalty in the Manchester derby on Sunday|
"Liverpool and United games over the last 25 years have been unbelievable.
"They've always been the most important games. It's shifted because at this moment Liverpool aren't challenging for the league like City are."
However, the United boss believes his side must relish the challenge of overcoming their fiercest rivals and cited a list of previous examples where the Red Devils have successfully done so.
He added: "Their fortunes changed the minute Sheikh Mansour took over. We know the minute that happened it was going to be a different ball game altogether.
"But, as we have in the past, we have to accept their challenge like we did when Chelsea came along and when Arsenal overtook Liverpool in the early 90s. We have to do it again."