Even now, outplayed by their oldest rivals, drifting further into mediocrity, the frustration and confusion and genuine shock manifested itself only in a loud, defiant show of support. At another club, they would be hounding the manager out by now.
They were abysmal, completely out-thought and out-done by a Liverpool side that passed the ball with much greater speed and intelligence and clambered back above Manchester City into second place in the Premier League.
Steven Gerrard initiated the ordeal with two successful penalties and, though he put a third one against the post in the second half, there was still plenty of time for another wretched day for Moyes to descend into even more of a mess. Nemanja Vidic was sent off for the third of the penalties and, soon afterwards, Luis Suarez was gleefully turning the ball past David de Gea.
There is now a 43-point swing in Liverpool's favour between these sides over the last year and, on this evidence, nobody should be reckless enough to assume their title challenge will simply melt away. Brendan Rodgers's team are four points behind Chelsea, with a game in hand, and still have to play them at Anfield. He is right, strictly speaking, when he says Chelsea and Manchester City are the more likely champions but Liverpool are playing with confidence and momentum and passing the ball in a way that was simply too much for their latest opponents. "We're going to win the league," their supporters were singing before the end. In the worst moments, Moyes's team seemed to get everything that is expected of them inside this stadium.
No side with Wayne Rooney, Robin van Persie, Juan Mata and Adnan Januzaj as its frontline should be this bereft of ideas or poor on the ball. Yet this is not a one-off. It was both shocking, yet not absolutely surprising, and the indignities continue to pile up for Sir Alex Ferguson's successor. "David Moyes is a football genius," was another chant from the away end. It has been the soundtrack to his season, and it might even get worse before it can possibly get any better. One certainty is that Olympiakos, with a 2-0 first-leg lead, will not be discouraged about their chances of completing the job on Wednesday.
They were lucky, too, that the referee, Mark Clattenburg, opted to show leniency to Rafael da Silva after his handball had given Gerrard his first chance from 12 yards. A minute earlier, Rafael had been booked for a scything challenge through the ball of the Liverpool captain. A yellow card is not mandatory for a handball penalty offence but a deliberate one, preventing Suarez from going around him, really ought to have seen Clattenburg reaching for his pocket again.
For Liverpool, it did not hugely matter. Rodgers had set up his team with a midfield diamond, with Raheem Sterling operating at its tip, just behind Suarez and Daniel Sturridge. That front three wreaked havoc and Liverpool might actually have had four penalties bearing in mind the moment early on when Jones and Marouane Fellaini both had a nibble at Suarez's ankles. That chance arrived from Mata losing the ball on the halfway line and the tone was set. This, more than anything, must be the greatest concern for United's supporters. Their team was so careless on the ball. Liverpool, in stark contrast, shimmered with self-belief. Gerrard dominated midfield with Jordan Henderson and Joe Allen, to the point there were callous cheers from the Stretford End when it was announced Fellaini was being substituted.
Gerrard's second penalty arrived inside the opening minute of the second half, after Phil Jones had barged over Joe Allen. Just like the first, Gerrard took it brilliantly to De Gea's left. On the third occasion, he went the other way and this time he misjudged his shot. United were incensed because it appeared Sturridge had dived over Vidic's challenge but the real story here was not of injustice. It was of the confirmation that Liverpool have caught and overhauled their old enemy.
United were hopelessly lost in those final exchanges, culminating in Suarez controlling Sturridge's miscued shot to complete the home side's misery.