The Premier League has never witnessed a finale like it and could struggle to match the breathtaking twists and turns for years.
After 38 matches over nine months, all that separated City and United was goal differential as the clock wound down on the season Sunday evening.
''I don't want to spoil the moment,'' City captain Vincent Kompany said. ''But I'm already looking forward to the next one.''
The final dramatic turn - injury-time goals from Edin Dzeko and Sergio Aguero - swung the title race back in City's favor when all appeared to be lost.
United's title celebrations at Sunderland, where the deposed champions had won 1-0, were abandoned as manager Alex Ferguson hastily ordered his players off the field.
''I got the word during the game that City had scored to make it 2-2,'' United defender Rio Ferdinand said. ''Then, after our game finished, it went flat and silent, with everyone waiting. The cheers from the home supporters let us know City had scored and the title had gone to them.''
At the Etihad Stadium, dejected fans, who had exited when City was trailing 2-1 in the 90th minute, clambered over walls back into the stadium to join the party through a blue smoke-filled haze.
By then, the scoreboard read 3-2, and a group of players who hadn't been born when City last reached the pinnacle of English soccer in 1968 were still stunned that they had pulled off the most miraculous of comebacks.
''You want to say it's the best moment of your life,'' Kompany said. ''But, if I'm honest, please never again this way.''
It was, though, ''a crazy finish for a crazy season,'' as manager Roberto Mancini said, sipping champagne.
A City title charge that at one stage had appeared unstoppable, looked to be over five weeks ago when United surged eight points clear and Mancini conceded the trophy.
The Italian hadn't factored in a United collapse.
''It's the hardest league in the world,'' United manager Alex Ferguson said. ''And anyone that wins it deserves it.''
As United has done 12 times in the 44 years since City's last championship triumph - all under Ferguson since 1993.
Even if City goes on to topple United as English soccer's dominant force, no title is likely to be recalled as fondly as its 2012 success.