It is the body language that reveals most on harrowing occasions such as this. Take the trudge back to the halfway line by Manchester United's players as the majority in this arena revelled in Samuel Eto'o's hat-trick goal, broken men shuffling back to their marks with no discernible anger etched across their faces. No furious rallying from the more experienced in their number. No real embarrassment at their desperate predicament. Just that hunched, haunted look of the defeated, resistance limp.
Or rewind further to the moment seven minutes before the interval when Danny Welbeck collected Adnan Januzaj's centre on the edge of the six-yard box and felt his ankle clipped by César Azpilicueta just as he scuffed a left-foot shot straight at Petr Cech. The striker should still have scored but had the foul on his standing leg not choked the attempt? Apparently not. David Moyes did not erupt in protest in the visitors' dugout but merely held his head in his hands, while Welbeck retreated sheepishly from the goalmouth. There was no outrage, no smouldering sense of injustice. Rather, the sense offered was one of resignation that United had undermined their own efforts yet again.
This club is learning to adjust its immediate expectations in its first campaign post-Sir Alex Ferguson. Reality bites when the numbers become this stark: 14 points off the top; 12 off third place; six from the Champions League qualification positions; seventh in the table with this a seventh league defeat in 22 games.
Yet there was a predictability about the latest loss that was damning. United may have been dominant for long periods in the middle third, their urgent start having shocked the home side and their frantic late rally prompting José Mourinho to end with three defensive-minded midfielders on the field, but they were sloppy where it counted. "We didn't do well enough in both boxes," said Moyes. The manager's assessment of his team's defending at set-plays was even more succinct: "Terrible."
The defensive vulnerability was unnerving, whether it was Phil Jones buying Eto'o's drop of the shoulder so readily before the striker's deflected opener, or Antonio Valencia obligingly spinning the Cameroonian on the goalline as if inviting him to prod in the third.
Likewise at Chelsea's second, when Gary Cahill had found himself unmarked, when he was free to nod at goal or to slide the ball across the six-yard box for the veteran forward to poach. Freeze the play at the moment the England centre-half crosses on the stroke of half-time and there are three United players standing level with the penalty spot, facing goal and aghast as realisation dawns that all semblance of defensive responsibility has exited the arena. From the moment Patrice Evra had clipped Willian's original corner clear they had switched off.
Some blame is down to depleted ranks or ageing bodies and minds. Rio Ferdinand is injured, Evra on the wane, Nemanja Vidic far from as imposing as he once was – and now harshly suspended for three games – but Moyes will wince at such disorganisation at routine set pieces. Lesser teams would expect to repel such routines and Chelsea have played far better than this plenty of times this season. They tend to scintillate in spells, rather than entire contests, but here they did not have to be at their best to prevail.
Eto'o and Willian were impressive in front of the watching Roman Abramovich, the two signings the owner had championed from Russian football coming good on a grand stage, and Eden Hazard can burst into occasions like this. But the visitors handed out gifts against a team whose own wastefulness has been a recurring theme. "Normally we need four or five chances to score," said Mourinho, "but today we scored with our first shot, we scored with our second shot … "
The home side's best performers, Eto'o the predator aside, were arguably their defenders, although perspective is needed there, too. In the absence of Wayne Rooney and Robin van Persie United can appear horribly blunt. Januzaj, alone, offers constant threat but it was already perverse that the champions should be reliant upon an 18-year-old whose entire senior career extends to this campaign. Freak injuries can occur at any club and to any player but United should expect more from their back-ups than what was offered here. Januzaj aside, where was the pizzazz up front? Where was the mystique? The answer, regrettably for Moyes, is probably in rehabilitation back at Carrington.
That is not a new problem but Chelsea merely exploited the fact that, at present, the management is offering few plausible answers on key occasions.
United have come from two goals down in the revamped Premier League to win five times, more than any other team, but there was no sense here that they would muster a sixth. This was all too reminiscent of the derby loss at the Etihad Stadium back in September.
The away fans' support was defiant and admirable to the last, and the locals celebrated with gusto at the end, but there was an element of the routine to all this. Beating United these days seems less of a demonstration of power – and Moyes will shudder at that reality.