Whether you are a Manchester United supporter or not, it's hard to argue with their ability to grind out results.
Sir Alex Ferguson and his 19 titles would be tough to refute in a debate, but when you look closely, you can see that at the core of the club's long run of success is the mental toughness needed to fight through rigid fixtures and tough opposition.
It is human nature to look at the games coming up and attempt to pick out the matches where your closest challengers will slip up and drop points and, six weeks ago, the City players would have seen United facing games against Arsenal, Chelsea, Liverpool and Tottenham and expected them to find it tough.
But United won at the Emirates, they fought back from 3-0 down to draw at Chelsea, beat Liverpool at Old Trafford and on Sunday, despite not playing particularly well, emerged with a 3-1 win at white Hart Lane.
Throw in their last-minute victory at Norwich last week and there can be no denying that United have laid down a marker and sent out a message to City that says, ‘right, come on then’.
At this stage of the season, it is not about being the best team or having the best players. It is about having the bottle and the belief to win the title.
Former Liverpool great Alan Hansen writes of how Manchester United's winning mentality means they can edge out City and remain Premier League top dogs.
If the pressure begins to tell, individuals begin to do their own thing and the collective suffers.
City have improved greatly since last season and it is incredibly difficult to separate them from United at the moment, but while United have been over the course and distance so many times, we still don’t know how City will react because they don’t have that experience of winning a title.
Clearly, the game between the two teams at the Etihad Stadium on April 30 is going to be pivotal.
Home advantage in that game, and their current two-point lead, ensure that City have something in their favour in what will be an intriguing run-in. But a quick glance at the fixtures between now and then suggests that City will do well to be on top when they face United.
Roberto Mancini’s team must face Chelsea at home and Arsenal away. United, on the other hand, don’t play another top-six team until they face City.
But the reality is that there are no easy games now. United have discovered that to their cost this season in losing at home to Blackburn and then being beaten at Newcastle.
They have also been hammered 6-1 by City and suffered an early Champions League exit, but while those defeats and setbacks would send a lot of teams under, United have picked themselves up and got on with it and they just keep getting results.
That is why I believe that United just have the edge and, if I had to back one of them to win the league from this point, I would favour them.
There is also the motivational factor of United being determined to stop their neighbours and city rivals becoming top dogs in Manchester.
United have been on top for so long that they will not want to contemplate surrendering their position to City.
There really is a different dynamic to a title race when you are vying with your closest rivals and I experienced it first hand when Liverpool and Everton contested the first division championship for four seasons in the 1980s.
For a long time Everton, like City, had not been particularly good and Liverpool had won lots of trophies to claim a position of dominance.
But Howard Kendall built a phenomenal side at Goodison Park and the fear of giving up top spot in the city was a real one for us at Anfield. It gave the title race a totally different feel when we were battling against Everton.
We were lucky, though, because although Everton won two titles, we claimed the trophy back immediately on each occasion. I’m not sure it will be quite so simple for United to do that, however, if City beat them to the Premier League title this season.
If City win this one, you can see them winning six or seven out of the next 10 because they will inevitably strengthen again.
But if United emerge as champions, the perception will be that City will have capitulated, having led for so long, and that will undoubtedly have a big effect on both clubs.
It would be a major setback for City and another example of United’s ability to win, regardless of the challenge in front of them, so it could be a momentous run-in.
And because the first title is so much harder to win than the fifth, sixth or, in Sir Alex Ferguson’s case, the 13th, United have the edge.