Whatever happened yesterday at the Emirates Stadium, and it could well prove to have been momentous, you couldn't shake away events less than 24 hours earlier in a different part of London.
You couldn't trust what the match officials saw, not after the Chelsea goals that never were, not after the latest evidence that football's refusal to employ, unlike every other major sport, the help of technology is thrusting it ever deeper into a time warp.
And, soon enough, you knew you were right to have withdrawn your faith in these men whose omnipotence is so relentlessly defended by the authorities.
The only mercy at the Emirates was that the human error this time went both ways and thus failed to distort the result of a hugely important game. Nemanja Vidic escaped the concession of a penalty, and a red card, when he palmed the ball out of the heading reach of Robin van Persie, a howling error that at least to some degree was balanced by the failure to penalise Gaël Clichy's blatant fouling of Michael Owen.
It meant that Arsenal and Manchester United received precisely their just deserts. Arsenal won after producing a performance that was a haunting rebuke to their latest failure to stay among the serious runners. In Aaron Ramsey and Jack Wilshere they were reassured that there may indeed be a flourishing life after Cesc Fabregas.
United lost a game they never looked like winning with a performance which gave much credence to those who say that whatever the competitive character they have at times displayed this season, a record-breaking 19th title would be an extravagant reward from a non-vintage season.
Of course, the odds still say it is likely to happen but there were times yesterday when it looked less a probability and more an outrage.
United once again revealed their quite shocking core weakness. It is the absence, beyond the flickering Indian summers of Ryan Giggs and Paul Scholes, of a midfield of anything like championship substance.
Nani was Nani, spasmodic at best, Michael Carrick was insipid and anonymous, a ghost of the player who on some recent occasions has promised some kind of resurrection and Anderson's claim that he is a potential player of the year made you wonder if he had gained access to some funny cigarettes. Even Antonio Valencia, whose return has at times looked like a potentially tremendous late-season boost, was stripped of wit and anything like bite. It was impossible to imagine this team, in this mood, improving one iota on their shocking abdication against Barcelona in the 2009 Champions League final when the likely re-match is staged at Wembley later this month.
In the meantime they must scrabble their way to the finishing line, a task that is obviously not impossible against a Chelsea who were comfortably dealt with in the Champions League quarter-finals and have not exactly been lighting up the heavens in recent weeks.
These are no doubt matters which will come much more sharply into focus in the next few days and weeks but in the meantime it is hard to be detached from the most persuasive message of this last weekend.
It is, surely, that the Luddite persuasion ruling football loses a little more credibility with each new piece of fresh evidence that technology has become so inevitable that the only question is how big an archive of lunacy will be created before the necessary action is taken.
For those who have argued for this for so long there is just one other question. How much scorn, how much hard evidence of on-going folly, needs to be produced?
We could start with the fact that the laws of football were first codified in 1863 or, put another way, before the American civil war was resolved, Leo Tolstoy published War and Peace and Mark Twain Huckleberry Finn, and, most relevantly, 63 years earlier than John Logie Baird provided the first demonstration of televised moving images.
Football must move on. The Luddite stupidity has rarely been exposed so pitifully, so ironically, as at Stamford Bridge on Saturday when Tottenham goalkeeper Heurelho Gomes reached back to prevent the entirety of the ball crossing the line.
As was true when Frank Lampard, the author of Saturday's speculative shot, was denied a perfectly legitimate goal in Bloemfontein against Germany in last summer's World Cup, the reality was evident to the watching world in no more than two seconds – long enough, though, for the assistant referee to flag the goal, from a hopeless vantage point.
Some have made the point that this decision, coupled with the fact Salomon Kalou was allowed to score the winning goal from an offside position, may have cost Spurs the £30m reward for qualifying again for the Champions League. In such a money-dominated game, this is no doubt a matter of some significance but it is not the basic point. This is that a game, in which quite incidentally Chelsea ultimately produced the stronger performance, was turned into a nonsense. It was made so by decisions which, in the second decade of the 21st century, could have been so effortlessly avoided.
All that was needed was a fourth official armed with technology and the power to correct, in no time at all, the most outrageous mistakes.
Referees, we are constantly told, should receive respect. It is an official FA campaign but it is one that is destined to be increasingly futile as long as a screaming reality remains unrecognised. It is that more than respect, match officials need help – and urgently.
Such assistance would have wiped out, also within a few seconds, arguably the most sickening consequence of the failure to enlist technological help. It was Thierry Henry's ability to earn France a place in the last World Cup by a piece of cheating instantly detected by all but the match officials. Arsène Wenger said at the time, "I felt sorry for the referee – he was the only one who didn't know."
Such institutionalised ignorance must surely be at the end of its run.