Not even the television cameras trained on the lower tiers could disguise the tumbleweed factor. The swathes of unoccupied sky-blue seats at the Etihad Stadium, or “Empty-had” as rival fans have grown fond of calling it, were so stark that you could make out the huge “City” sign spelt out in white across the East Stand. Official attendance for the visit of AEK Athens confirmed the alarming optics: 40,042, in a ground with a 61,000 capacity. At a time when Manchester City are failing to convince anybody of the legitimacy of their path from relative global obscurity to reporting greater commercial revenue than Real Madrid, it was, shall we say, not the best look.

To quell the inevitable howls of outrage from City supporters, we should point out that there were mitigating factors. This is a club that has gorged on glory so ravenously for the past 15 years that a midweek collision with the champions of Greece struggled to stir the soul. Add the fact that it was just six days removed from a frenzied scrap with Paris St-Germain, the game’s ultimate sophisticates, and you can understand why it had a distinct “after the Lord Mayor’s show” feel.

But the reality is that this ghostly spectacle is anything but an outlier for City in the Champions League. Unless the opponents are multiple European champions, the sense of listlessness is palpable. Just 35,259 attended the home game against Galatasaray last January, while even the more seductive match-up against Napoli last season enticed 49,531, just 81 per cent of the possible total.

Except, fashionable though it might be to puncture City’s delusions of grandeur, the explanation goes deeper than a single club’s inability to sell out. For the continent’s big beasts, the engorged league phase of this competition, stretching inelegantly into late January and requiring eight games rather than the previous six, is simply too inconsequential and too light on jeopardy to hold the attention.

The recent goal gluts are a case in point. “Are Paris St-Germain just going to beat everybody 4-2?” asked Sam Matterface, after the reigning champions followed up their exquisite filleting of City by beating Barcelona by the same scoreline. In all likelihood, no. As soon as the knockout rounds begin, all indications point to such contests being tighter, tenser, with a defensive robustness proportional to the stakes.

Since both PSG and Barcelona recognise that five wins out of eight will shepherd them safely into the elimination phase, they are minded to chase victory when they play each other, reassured that defeat is hardly terminal. Rodri looked far from distraught by the result at Parc des Princes, and why not? His team need three more wins to guarantee qualification, and with Sabah, Sporting Lisbon and Como still to come, that prospect is far from daunting.

City can afford to adopt the same attitude. Once, conceding three goals to PSG in 32 minutes might have been an ominous portent for their hopes of progress. Today it is barely a bump in the road as AEK are the type of cannon fodder to enable Phil Foden, without a goal for 10 months until last Saturday, to plunder a hat-trick.

The upshot is a set of games so featherweight in competitive magnitude that they resemble exhibitions. So far in the Champions League this campaign there have been 187 goals, at an average of 4.16 per game, rivalling even the chaotic early years of the European Cup. The average for the 1959-60 season, which culminated in the unforgettable score of Real Madrid 7 Eintracht Frankfurt 3, was only fractionally higher at 4.19.

There is no disputing the entertainment value of watching Liverpool vanquish Villarreal 4-3 at Anfield or LASK, the Austrian side making their debut at this level, 6-3 in Linz. The more fraught task is determining what any of it means. With a goals boom dwarfing anything witnessed in the domestic leagues – La Liga is stuck on a mere 3.03 goals per game, and the Premier League on a frankly miserly 2.69 – the Champions League is undoubtedly the place for instant gratification.

Without a goalless draw in sight, the latest instalment served up 40 goals on Tuesday night alone, fresh from last Wednesday’s record return of 46. And yet the sheer openness enabled by the Swiss-league model the lack of immediate consequence, has brought defending of a nonchalance that borders on casual.

At one level, PSG’s sumptuous duel with Barcelona was a masterpiece of branding, featuring loving cutaways to Lenny Kravitz in the crowd and a typically inventive strike by Lamine Yamal, the most exhilarating young player in the world. But at another, it smacked of a Super League by stealth, a means of satisfying Uefa by throwing two of the best teams together in the autumn, while ensuring neither fell by the wayside before the spring. While the ensuing free-for-all was a feast for the senses, the impression of artificial engineering was not.