He recognises the positive impact another win could have on Martin O'Neil's team - not to mention doing his old club a huge favour.
"Everything about it was perfect on the day," said O'Shea of last season's encounter. "We had to defend so well together as a team and then in the last few minutes we got a counter attack and scored a great goal.
"That win lifted everybody going forward. Wins like that can have that sort of impact and, fingers crossed, it will be the same again. We will have to defend very well again because when you look at how their attacking players link up it's going to be difficult.
"I watched most of the City game against Newcastle recently and they played some attacking stuff. Then when you look at how well United played against us at times, how fired up they are to get the title back, obviously it's going to be an interesting battle.
"United have the edge at the minute and they have good goals in their team. It will be interesting for City to see if they can catch up."