Two factors have gone against Roberto Mancini's men, though, neither of which they can do much about.
Manchester United have the psychological edge over City
Manchester City have not put up a bad defence of their title.
They have lost only three games, the same as a United side who are 12 points clear of them.
City have the best defensive record in the league and their squad is almost unchanged from last season.
Given the great players they have up front like Sergio Aguero and Carlos Tevez, I am surprised they haven't scored more goals, but defending the league title is more difficult than winning it because every team wants the scalp of the champions.
Two factors have gone against them, though, neither of which they can do much about.
Manchester United are motivated by failure. I have spoken to the United players who were at Sunderland last season and they never, ever want to experience that feeling again.
They went from thinking they were going to win the league to losing out to their neighbours in the final minute of the final game.
I have experienced a similar feeling, in 1995, when United lost the league on the final day of the season. It is awful. I made sure that I was as focused as possible a season later and we won the double.
The second factor is Robin van Persie, who has been an unquestionable success for United.
The Premier League is not as strong as it was five or 10 years ago. Arsenal, Liverpool and Chelsea are all weaker than they were. Only City have got stronger, thanks to massive investment.
They have a great squad, but can they close a 12-point gap? I doubt it. Roberto Mancini said that his side will capitalise if United drop points.
United will drop points, but so will City - they are dropping points every game, at present.
And why have City let such a lead develop in the first place?
It is partly because United are on for a record points haul, partly because City have drawn too many matches. But I sense no urgency about City.
I saw them lose to a really impressive Southampton side. They needed a player to take control, to inspire. They did not have one that day.
City players seem sated by their success, as if winning the league once was enough. United meanwhile, have already beaten all their main rivals away.
But how do you close such a gap?
I have been the hunter and I've been the hunted. For United, we chased down Newcastle in 1996, beat them at their place and went on to win the league.
As City's players know from last season, when you smell blood and sense a weakness, you gain an extra incentive.
You just do. You give more.
And all the better if you see rivals losing it, like Kevin Keegan did live on TV in 1996. When we saw that, we knew Newcastle were cracking.
And I have been the hunted, in 1998, when Arsenal beat United at Old Trafford and did to us what we had done to Newcastle.
It is horrible. Nerves and doubts creep in, problems are exacerbated. How can you explain United 4, Everton 4 from last April? Even now the players don't know what happened.
If City can close the gap to six and then beat United at Old Trafford at the start of April, they will feel a surge of adrenalin and hope.
They will think that history will repeat itself and know that there are still six or seven league games left, but I cannot see United slipping.
United's run of league matches until the derby is not difficult: QPR today, Norwich, Reading and Sunderland.
City play Chelsea tomorrow, Villa away, Everton away and Newcastle at home. United should be 12 clear going into the derby, maybe more.
Do not read much into United having Europe distractions, they've been in Europe after Christmas almost every year for 20 years. They know what they are doing: been there, done that.
City are the team out of form, too, without a win in their past three. And City are the team who were unbeaten in the league until United beat them in December. There's only one team winning the psychological battle this season and they wear red, not blue.
City's players are sending out mixed signals, suggesting that they will win a trophy to keep Mancini in a job. Do they know something we don't?
Uncertainty like that doesn't help, nor does a manager finding fault with a player, like Mancini has done with Joe Hart.
Criticisms are best kept in-house. Do it in public and you lose your players. I know, I've been there.
I had expected a closer title race, not just from City, but from Chelsea.
I expected Arsenal to be stronger, Liverpool, too.
Neither of them were going to win the league, but I did not expect them to draw or lose more games than they have won.
The league's not over, but I had be stunned if United lost it, especially after what happened last year.
Andrew Cole's column is written with the assistance of the European football correspondent Andy Mitten.
Follow us @SprtNationalUAE