After all the false dawns, a cynic would say Arsene Wenger has as much chance of winning the Premier League as Jeremy Corbyn has of winning a general election from his constituency of Islington North. But at least the 20th anniversary of Wenger's arrival on Corbyn's patch met little resistance from the opposition in blue.
Anniversaries have tended to be painful occasions for the longest-serving Premier League manager, the embodiment of stubbornness in a capricious world.
Wenger's 500th match in charge brought a 1-0 defeat by Chelsea. His 1,000th game was humiliating - a 6-0 beating at Stamford Bridge that really did feel like the beginning of the end for a manager obsessed with a good idea gone bad.
If Wenger could have designed his 20th anniversary shindig, it would surely have featured a resounding victory over Chelsea, the West London fortress from where Jose Mourinho fired so many personal attacks. "Yes, I would like us to be 3-0 up after 40 minutes," Wenger might have told the party planners, "with goals from Alexis Sanchez, Theo Walcott and Mesut Ozil, scored against a shambolic Chelsea defence, with the home crowd ecstatic.'
Well, Wenger was granted all those pleasures, as the frailties exposed by Liverpool at Stamford Bridge expressed themselves again on the other side of London. First, though, we ought to acknowledge the lethal silkiness of Arsenal's attacking: the sweep and syncopation of their forward play, which is Wenger's idea of heaven.
A training video of the idea that has driven him for two decades would look a lot like Arsenal's second goal here, with its side-to-side swagger, which left Chelsea's defenders dazed and confused. Or their third, made up of sweet interplay between Ozil and Sanchez, with an Ozil volley driven into the ground and over Thibaut Courtois.
Wenger was due a happy landmark day, especially as Chelsea have caused him so much bother down the years. The Arsenal manager won 15 of his first 27 confrontations with Chelsea but only five of the next 27 as their London rivals perfected the art of burrowing under their skin (and seeing Arsenal players sent off). Chelsea had not lost to the Gunners in nine Premier League fixtures and were unbeaten in the league here at the Emirates Stadium since 2010.
Strictly, Wenger first stepped into the dugout on Oct 1, but this week brought the 20th anniversary of his appointment, returning us to a time when footballers supposedly had steak and ale pie and chips for breakfast, followed by six pints of lager and a jumbo packet of cheese and onion crisps for lunch.
Talk of the "impact" Wenger made on English football sounds a little dated now, because the whole game is unrecognisable from the world he entered in 1996.
He certainly made an impact on Chelsea, who have been given the runaround by two good sets of attackers within nine days. Specifically, Gary Cahill and Branislav Ivanovic are currently a liability in Antonio Conte's back four. They conspired in Arsenal's opening goal when Ivanovic played a risky pass back to Cahill and the England centre-back miscontrolled it, allowing Sanchez to surge through and finish with a delightful chip.
From there Conte's rearguard were a mess of back-pedalling, poor co-ordination and panic on the edge of their penalty box. It is a travesty for Chelsea's fans that their team remain so reliant on the 35-year-old John Terry, who is still injured. Without him, the basic art of stopping breaks down, and the back four's confidence seems to go. The discomfort only grew when Ivanovic blasted a shot over from long range with 23 minutes left and Conte turned away, unable to take any more.
By then Arsenal had wasted several chances to push the scoreboard towards the 6-0 of two years ago, only this time with Chelsea on the receiving end.
Wenger could be forgiven a flash of schadenfreude too when Cesc Fabregas was hooked by Conte early in the second half. Fabregas, of course, was one of the leaders of Arsenal's talent drain.
The beauty of sport is that it is unscripted. But sometimes you feel we already know the Arsenal story, or how it will turn out. It will be a tale of radiant periods followed by confusion, let-downs and anger. At the centre of every discussion will be Wenger, who has presided over 1,128 games over 7,299 days in charge.
Is he like a great actor who has hung on too long, leaving the audience wanting less, not more? Is this the longest masterpiece ever in the making or will it always lead inexorably to second, third or fourth place - and a Champions League second-round exit? These big questions will not go away just because Arsenal blew away a disorganised Chelsea side inside 40 minutes.
But it was quite something to see Wenger, 20 years on, doing unto a major rival what the major rival had done unto him, only two years. Quite something, in fact, to see him chasing the same ideal, two decades after he first made it his manifesto here in England.
Reverting to a less appealing type, Arsenal tried to gild the lily with their forward play in the second half, while Chelsea switched to a back three in desperation. Successive defeats in London by Liverpool and Arsenal suggest Chelsea have a lot of thinking to do about how they build their squads.
The former Arsenal vice-chairman, David Dein, has revealed that when he first socialised with Wenger the club's future manager acted out scenes from A Midsummer Night's Dream in a game of charades. Presumably he recited the line: "The course of true love never did run smooth." It ran nice and smoothly here.