It is one of football's great beauties that it can be played in such a variety of ways. There may be a consensus at the moment among the elite that favours pressing and possession, exploring modern interpretations of total football and proactivity and nudging up goals per game ratios across the major leagues, but there is also an alternative strand of thought, one that does not engage high up the pitch but prefers to sit deep and thwart the opposition, looking to play reactively, and at that José Mourinho remains a master.

A slight gloss, perhaps, is needed. To say a team plays reactively is not a criticism. It is not to say that they are negative or defensive or that they park the bus – not that there is any shame in that, whatever Mourinho himself may have suggested after last week's draw against West Ham. Reactive teams – Germany at the last World Cup, for instance – can still play thrilling and aesthetically pleasing football. Bayern Munich, in their Champions League semi-final victory over Barcelona last season, were reactive, allowing their opponents long spells with the ball before picking them off. And Chelsea were reactive in beating Manchester City on Monday night.

Again and again City attacks broke down and Chelsea stormed forward on the break, awesome in their pace and muscularity. Watching Willian and, particularly, Eden Hazard, surging into space, creating angles for each other, always driving, it was easy to see why Mourinho felt Juan Mata had no place in his side: wonderful talent that he is, this is not Mata's type of football. What was striking as well was how bad City were at countering the counter: when was the last time, at Premier League level, other than in the final minutes as one team gave in to desperation in chasing the game, that you saw a team have a four-on-two break as Chelsea did after 27 minutes?

John Terry suggested that his side's victory was significant not merely for the three points it brought, drawing Chelsea within two points of the top of the table and preventing City moving six points clear of them, but also for the encouragement it might offer other sides going to the Etihad, "showing they can be beaten".

Perhaps that is the case – it seems, after all, fairly well attested that once a team develops an aura opponents seem almost unconsciously to accept a narrow defeat rather than risk humiliation. Manchester United's current travails are at least in part a result of the dissipation of their aura and it is certainly worth reminding teams that, for all their attacking prowess, there is a soft centre to this City – but it is hard to imagine many other sides being able to hold City at arm's length as well as Chelsea did.

What Mourinho has done over the past month and a half has been remarkable. The defeat at Sunderland in the Capital One Cup on 17 December was a Rubicon. His side had been on top for much of the game at the Stadium of Light, but then conceded a sloppy late equaliser and ended up being pummelled in extra time. Mourinho afterwards seemed drained and you wondered what toll all the battles at Real Madrid had taken on him. But in his weariness, there was a resolve: he would go back to basics, he said, for, he claimed, there is nothing easier in football than winning 1-0.

He had six days to work with his side before the league game at Arsenal and it seems most of it was spent on refocusing minds and getting the defensive shape right. At the Emirates he played a 4-3-3, closed down an Arsenal midfield that at the time seemed rampant, and came away with a 0-0 draw. Moreover, Mourinho seemed much cheerier, back to his mischievous best, as though the Sunderland defeat had resolved a dilemma, turning him to a course of action on which in his heart of hearts he had always been set.

The 4-2-3-1 has returned since then –although you wonder whether it might have been 4-3-3 again on Monday had City's Fernandinho been fit – but Chelsea have stopped conceding: in 10 games since Sunderland they have let in just two. The weird laxity at set plays has gone, the shape is better, the cover is better – and, worryingly for opponents, their transitions are getting better and better.

City had 65% of possession on Monday, but managed only three shots on target. West Ham had one; Stoke had one; Manchester United had four; Hull had two. Chelsea have become supremely adept again at shutting down what Ottmar Hitzfeld terms "the red zone", the central area just outside the D from which most shots or decisive passes come.

Sides such as Bayern Munich and Barcelona deny opponents access to that key sector by pressing high up the pitch, squeezing them back in their own half and then denying them possession. Chelsea do it with guards, stationing Terry and Gary Cahill within the zone – one of the reasons Terry suddenly looks so good again is that he is defending deep, playing with with the game in front of him so his lack of pace and consequent vulnerability to balls played behind him is no longer an issue. At City, Nemanja Matic and David Luiz were just in front.

Although City had plenty of the ball, they were unable to play through that area. It is true they were hampered in that by the absence of the injured Sergio Agüero but, at the same time, had he been able to find pockets of space, Chelsea could always have reverted to a 4-3-3 and brought Ramires back to add an extra body to plug up that zone.

It is not a particularly modern way of defending or a fashionable one, but it is an effective one. And, in a world in which possession and proactivity are dominant, Mourinho's difference should be celebrated.