A catastrophic sequence of results, which saw United claim only one win in their next four matches, allowed City to edge clear of them on goal difference after their momentous 1-0 win over their neighbours on April 30.
No team has ever lost the title after leading by eight points in April, and Ferguson must now come to terms with the fact that his side have done a "Devon Loch", the horse which mysteriously collapsed 40 yards from the finish line when leading the 1956 Grand National by five lengths.
Ferguson is in no doubt about the result which proved pivotal in his team's demise, namely the 4-4 draw with Everton on April 22 which allowed City to move within three points of United.
Had United been able to claim all three points after leading 3-1 and 4-2 at Old Trafford during the second half, they would be still be two points clear heading into Sunday's final round of fixtures.
"I think the Everton game was the killer for us," Ferguson reflected last week. "It was an absolutely ridiculous performance in the last 10 minutes of the match. Just absolute carelessness," said Ferguson.
"If we lose the league we'll have to accept it's the Everton game that did it. No doubt about that."
If City do become the first team in the Premier League era to clinch the title on goal difference this weekend, Ferguson's words following that traumatic defeat at Old Trafford will haunt his players.
It has left Ferguson hoping that a 2011/2012 season of the unexpected has one final twist in store on Sunday as his team travel to Sunderland.
But United's performance at the Stadium of Light will be irrelevant if Manchester City beat relegation-threatened Queens Park Rangers at Eastlands.
Regardless of the result, few will argue that the current campaign has been among the most compelling in English football history, which is set for the closest finish since Arsenal pipped Liverpool to the old First Division title in 1989 with their last-gasp 2-0 victory at Anfield.
This season is also on course to be the most prolific. With 10 matches left 1,034 goals have been scored - 30 more on Sunday would break the existing record of 1,063 set in the 2010/2011 campaign.
-AAP