For Manchester City , the pattern is becoming familiar: the trait that was once (and is still) the trademark of its arch-rivals United has been adopted wholesale.

City was behind against Southampton , but came back to win. It was twice behind against Liverpool but came back to draw. It was behind against Stoke and came back to draw. It was behind against Fulham and came back to win. It was behind against West Brom with 10 men and came back to win. And on Sunday it was behind against Tottenham and came back to win. Whatever else can be said about Roberto Mancini's side, its character when behind can't be faulted (although United is still the king of giving the opponent a start, having come from behind to win eight times already across all play this season).

Against Spurs it was, again, Edin Dzeko who scored the winner - his fourth goal as a substitute, all of them scored after the 80th minute, in the last six weeks. The Bosnian remains a difficult player to read, looking at times almost unplayable, a pulsing blend of muscle and touch, and at times desperately ungainly. When he is confident, though, as he is at the moment, he can be devastating; as David Silva's chipped pass fell to him against Spurs, there was not the slightest doubt that he would crash it into the roof of the net. In the way he addressed the ball, waited for it come into his stride, was a reminder that he and the largely unsung Grafite, now winding down his career in Dubai, between them inspired Wolfsburg to the Bundesliga title in 2009.

The theory with Dzeko always was that he needed a run of games to find that confidence and that he therefore wasn't suited to a team like City, in which the size and quality of the squad makes rotation a fact of life. It seems a run of substitute appearances is enough, although Dzeko clearly wants to start games. He had said before the game that he hates it when he is called "a super-sub"; afterwards he insisted his goals were "a message" to Mancini.

Dzeko is becoming to City what Javier Hernandez is to Manchester United.

"A player so strong of character like Dzeko to come on when his team needs him deserves great credit," the Spurs manager Andre Villas-Boas said after the defeat.

Yet while Hernandez, at the beginning of his career, seems cheery enough in the role, Dzeko, reaching his peak, is not. "He is not happy," said Roberto Mancini. "A player who is happy on the bench does not exist."

That's not necessarily a problem, even it does add to the vague background sense of discord that always seems to hang around the Etihad. In fact, to an extent it's inevitable when clubs stockpile resources in the way the elite do in modern football - and, of course, it represents their strength. That United and City can afford to leave the likes of Hernandez and Dzeko in reserve is precisely why they occupy the top two positions in the Premier League.

Yet the difference in attitude between Dzeko and Hernandez - and Dzeko's willingness to let his grumpiness show - feels telling. Morale at City always seems fragile, something that can't have been helped by the revelations about Mancini's dalliances with Monaco last season. After all, if the coach was willing to jump ship (admittedly perhaps pre-empting being pushed) when it looked like City wouldn't win the title, why should any player feel any great commitment? It may be, as the Aberdeen, Tottenham and Barcelona forward Steve Archibald commented, that team spirit is an illusion glimpsed in the moment of victory, but there must surely be some effort to keep up appearances.

And even beyond that, the question remains why United and City fall behind so often. Both seem to have adopted a self-consciously more open, possession-based approach this season and it has left them vulnerable. Domestically, both keep getting away with it. In Europe, United has as well - so far. But City, in a much tougher Champions League group, has been found out.

Blaming the manager is often no more than kneejerk scapegoating, but there are issues for which Mancini and his coaching staff must be held accountable. Why has City so often been so narrow, something that allowed Cristiano Ronaldo and Marco Reus such space for Real Madrid and Dortmund ? Why has City become so bad at defending set-plays that 60% of the goals it has conceded this season have come from them? And why, as Micah Richards admitted, are City's players so frequently confused by their manager's tactical switches?

To give him credit, on Sunday, Mancini got the tactical switch right. The move to a back three gave City numerical dominance in midfield and that was what led, indirectly, to the Yaya Toure surge that brought the equalizer. And he then brought on Dzeko who got the winner. But the sense is still of a club struggling with itself, being dragged along by the ability of a handful of individuals rather than any great collective purpose. Mancini's job is to ensure that by the end of the season these awkward weeks are seen as teething problems on the road to excellence; the danger is they become the weeks when the rot set in.