United make the short trip to the Etihad Stadium for the 1.30pm kick-off, live on Sky, with a three-point cushion over their arch-rivals seven months after seeing their Premier League crown snatched away on goal difference.
And with Roberto Mancini's men playing soon after their miserable Champions League exit and their manager highly critical of his lacklustre attacking force, Rooney believes momentum in the title race has shifted towards the red side of the city.
"If we win it will put more pressure on them," the 27-year-old England star said. "Three points would be massive. Us going six points clear would be a big statement.
"With City out of the Champions League, they are having a bit of a tough time - I think everyone can see that.
"We're in a great position and don't want to give it up. There is a big rivalry, the two of us are fighting for that no 1 spot."
City can boast a perfect record from last season after a 6-1 demolition at Old Trafford, before a hard-fought and decisive 1-0 win at home with two matches left before the end of the campaign.
Sergio Aguero's last-gasp winner against QPR on the last day of the season was the goal that provided City their first top-flight trophy for 44 years.
Rooney added: "It still hurts, yeah, of course. But that's gone now. We have to look forward to this season."