His performance against Bayern Munich was his worst of a season that has not quite started for Yaya Toure, who looks disinterested after a summer of unrest...
A disastrous night on which Arsenal were humbled by a side with which they should at least be competing. How much is Arsene Wenger to blame for a repeated failure?
It may have been a filthy, stormy night in Manchester, but lightning refused to strike twice for Liverpool. Aston Villa may have shocked Manchester City earlier in September after twice falling behind, but as soon as their defensive resolve had been broken on Wednesday, the home side simply effortlessly slipped into a higher gear. A single point is now all that is required for a second title in three seasons.
There was plenty of audible anxiety and bitten nails during a dire first period at the Etihad, a half in which City's dominance of possession and territory led to just a single shot on target. However, the concerns of City supporters that their perennial insistence on doing things the hard way was returning were relieved after Edin Dzeko put the ball through the legs of Brad Guzan midway through the second period. It predictably opened the floodgates, or at least left them ajar.
Dzeko may again take the plaudits, and indeed the Bosnian now has 24 goals for the season, but this was an evening on which a more unsung hero once again impressed - Pablo Zabaleta was the catalyst for all that City achieved. There is a fair argument to suggest that this is the most consistent right-back in Europe (at a third of the cost of a Glen Johnson too), over the past two years.
Such is his importance to City's defence, it now seems utterly unthinkable that Zabaleta started just 18 matches during City's title win of 2011/12, with Micah Richards instead more generally preferred by Roberto Mancini. How things have changed - whilst Richards has played just 161 minutes in the league under Manuel Pellegrini, no City player has spent more time on the pitch than Zabaleta. Whilst Vincent Kompany and Martin Demichelis have suffered from losses of form or concentration, Zabaleta has been the rock.
Despite City generally forced to withstand less pressure than the majority of other sides, only three Premier League players have made more tackles than Zabaleta this season. It sounds clichéd and hackneyed, but this is a player who evidently wears his heart on his light blue sleeve.
The right-back's positioning and marking have also improved hugely from two years ago (although his disciplinary record and temper remains suspect), but it is his stamina and determination that remains the most impressive of all. Against Aston Villa he won possession on ten occasions (no other outfield player managed more than seven), demonstrating the Argentinean's desire to harry opponents when on the ball. He covers more than 10km per game as standard.
Facing an opponent that posed very little threat in attacking areas, Zabaleta had licence to attack down the right wing. With James Milner tucking inside, Zabaleta's right-back position became a nonsense - his average position was in the Villa half and he made 68 of his 97 passes ahead of the half-way line.
Aleksander Kolarov may view himself as the epitome of the modern attacking full-back, but the Serbian has an element of inefficiency as the obvious chink in his armour. Kolarov gave the ball away with a quarter of his passes in opposition areas, and too often his crosses are over-hit or inaccurate.
On the opposite flank, Zabaleta is almost metronomic. He misplaced just five of his 97 passes (and just two in Villa's half), and claimed an integral part in both of City's opening two goals. Possessing a vital ability to make his overlapping forward run at the exact moment so as to maximise potential danger, the difference between Zabaleta and Kolarov is the former's calmness when in attacking areas. Kolarov tends to rely on power, whereas Zabaleta prefers precision.
This week, the dangers of City's wanton desire to spend vast sums of money has been made starkly apparent, so it seems vaguely ironic that perhaps the club's most consistent performer joined the club before Sheikh Mansour had even dumped his billions in Manchester. The £6.5million they paid Espanyol in 2008 might just trump any arrival since in value-for-money terms.
Left on the periphery in 2012, it seems fitting that Zabaleta should have such a hand in City closing in on the title once again. On Sunday I wrote of the likelihood that Bacary Sagna may leave Arsenal this summer, and City are the strong favourites to sign the Frenchman. Sagna's move may well be financially motivated, but that might be just as well. Zabaleta fought hard to gain his place amongst City's Galacticos. He will be damned difficult to shift.
Daniel Storey - Follow him on Twitter.