For starters, Arsene has never been called “the enemy of football”, as Uefa referees’ committee chairman Volker Roth described Mourinho as long ago as 2005, words that may partly inform Mourinho’s devout belief that every referee in Europe has since been recruited in a co-ordinated conspiracy against him.

He stayed loyal to those principles this week, complaining about the refereeing following United’s win over Northampton. But little else about him carries that kind of conviction any more. And as the first mutterings of what they called ‘palpable discord’ at Stamford Bridge begin to leak out of the Manchester United dressing room, maybe it’s time to ask what Wenger has broken in Mourinho.

On some existential level, has Mourinho been beaten by the man who has never beaten him on the pitch? From Mourinho’s vantage point, it is Wenger who might easily be regarded as the enemy of football.

This habit we have gotten into, of celebrating contrived milestones — 1,000 games, 500 wins, 20 years — might just be a symptom of Arsene’s sinister efforts to buck the natural rhythms of team sport, which is to measure progress at the end of seasons. And with trophies.

Conveniently, the essential differences between Wenger’s and Mourinho’s ideas about the passing of time are set out in their work for Swiss luxury watchmakers.

Wenger is an IWC Schaffhausen ambassador. Mourinho is a Hublot man.

In their recent promotional efforts, we see much to link the pair, a certain sense of style, I suppose, but chiefly an eye for a few quid and a knack for suitable bullshit when the need arises.

But even in the sales guff, there are subtle, telling differences.

Wenger: “I am not so much a watch fanatic. But I like the whole atmosphere, the creativity of the company. I have a feeling that IWC is a family, similar to a club.”

Mourinho: “I am a watch fanatic. I am honoured to be part of a brand that upholds such similar values to me.”

From there, they part ways entirely, Mourinho telling us last year how he marks success in timepieces.

“When I finish a season with a trophy, that season is represented with a watch.”

Victory is locked away in a safe, a new watch sourced. But if a season ends in failure, he wears the same watch again the next.

In a cruel irony, Mourinho began last season sporting Hublot’s ‘King Power’ model, which is where his second Chelsea coming ended. Presumably, he is still wearing it for Leicester’s visit to Old Trafford today.

Earlier this year, when IWC asked Wenger to select his career highlights, he went in a different direction.

“When people speak about highlights, they only speak always about trophies. It’s true the trophies you win are highlights but what you keep from your career is more human things.

“More that sense you could influence people’s life in a positive way. You could help careers to take off.

“Moments where that sense of unity was real, and not fake, that we were all on board to fight together, we were all on a high together.

“These moments are of course linked with trophies but not only. You remember more the human experience, the moments when your team played fantastically well.

“Sometimes, it’s only five minutes in a game. But you strive for perfection and when you reach these moments they stay in your memory forever.

“It’s worth to do it. And let’s do it again.”

Wenger’s critics will argue it’s easier to achieve success if you measure it in five-minute chunks rather than over 38 games.

With this kind of dangerous, anarchic talk, perhaps one day he might even be seen as the great corrupting force that undermined the very foundations of competitive sport.

This philosophy has given him unrivalled ability to wait; for the right player, at the right price. For the next trophy.

And it is the kind of ideal Mourinho assured us he wanted when he began his second term at Stamford Bridge. To be at the club for 10 years. To wear the same watch for a couple of seasons, if that’s what it took.

But before long, with Mourinho, the sense of unity tends to be exposed as fake.

“I need to feel comfortable and I like to be where I am truly wanted,” he said, before finally getting the Old Trafford gig he craved, but as he lashes out at one player after another, there is no sense yet that anyone’s life in being influenced in a positive way.

Now, after the latest revelations, it looks like he can’t even keep his favoured journos onside.

Yet for all Mourinho’s fighting talk, it is Wenger who lashed out when they squared up on a touchline.

That fierce competitive desire has kept him afloat, even as he waits.

He goes on, in that IWC chat, to talk about the most important qualities in a footballer. But he might as easily be describing his own ability to survive without the constant need for a reboot every two or three years.

“The most underrated quality is the stamina in the motivation. Perseverance.

“Very few people are capable to have a long-term target and to maintain the intensity of their focus no matter what happens emotionally. That makes careers. Everything is quick. You are questioned every day. You have one bad game as s player, you are absolutely useless.

“To keep that motivation and belief very high and to focus on the target and on improvement, it is an attitude that is essential.”

But why, amid all the waiting, has there has never been palpable discord in the dressing room?

Adrian Clarke, quickly rejected by Wenger 20 years ago, shared with FourFourTwo magazine this week the human things he has kept from his brief Arsenal career.

“Before I’d sat down for my first proper conversation with him, I could tell he was a nice person. When joining in with impromptu kickabouts before the warm-up - looking a touch awkward on the ball, I have to say – there was a kindness and vulnerability about him.”

Kindness wouldn’t have got him 20 days at Arsenal, never mind 20 years.

Perhaps the watchmakers captured the most significant difference between him and Mourinho, who tends to find leaks and rats and conspirators where ever he turns. The final question Wenger was asked, at the IWC gig: What is the most inspirational thing someone has ever said to you?

His answer: “I trust you.”