Ferguson initially seemed unconcerned when City's Abu Dhabi-based owners started lavishing vast sums on a host of big names three years ago.
But his dismissive jibes about dealing with "noisy neighbours" have been replaced by an awareness that Roberto Mancini's expensively assembled team are now a serious threat.
Now Ferguson has paid City the ultimate back-handed compliment by starting his mind games before the season has even begun.
He chose the eve of this weekend's traditional curtain-raiser to issue a stern reminder that splashing the cash doesn't necessarily mean prizes will follow.
"We get this almost every year when clubs round about us buy, and that's how you view the importance of winning the league these days," Ferguson said.
"Chelsea had this great spell of buying when Jose Mourinho first went there and we accepted that challenge.
"To win the league in England is very difficult. If you look at the Premier League you are looking at the top six fighting for four places.
"I think 84 points will win the league next year. We had less last year but you have to consider the increasing competition.
"Liverpool are expected to be better, the top four we know about and Tottenham as well. You expect it to be a really tough league."
Despite Ferguson's attempt to pile pressure on City, the Scot has spent nearly as much as Mancini since the end of last season.
While City's $79.64 million spree netted Sergio Aguero, Gael Clichy and Stefan Savic, United paid $78.08 million for David De Gea, Ashley Young and Phil Jones.
De Gea and Young are likely to feature for United on Sunday, while all three of City's new buys should be involved at some stage.
Aguero, City's record $59.34 million signing, will be among the substitutes at the start after suffering blisters while wearing the wrong size boots in training.
City's unsettled captain Carlos Tevez -- who hopes to engineer a move to Inter Milan -- will be absent until next week after playing in the Copa America, giving Mancini a chance to show if he retains faith in Mario Balotelli after falling out with the temperamental Italian in pre-season.
United have appeared in this event 18 times -- winning it against Chelsea 12 months ago -- since City last took part in 1973, but the champions are up against a team on the rise after last season's FA Cup triumph ended 36 years without a trophy.
Mancini's men enjoyed a memorable 1-0 semi-final win over United at Wembley en route to that final victory against Stoke.
Yet Ferguson insists the fixture is nothing more than a high-profile opportunity for his players to improve their fitness before the Premier League kicks-off next weekend.
"It's very easy to get emotional about this type of game. I don't think we'll be changing our policy," Ferguson said.
"I've always viewed the Community Shield as a stepping stone for the first game of the season and there are two or three players who will need a game to boost their fitness."