Each sub helped: Richarlison added much-needed aggression up against Gabriel and William Saliba; Yves Bissouma complemented Sarr; and, most important of all, Brennan Johnson’s direct running was a major upgrade down Spurs’ right.

Arguably the biggest reason for Spurs’ late surge was an Arsenal substitution. Gabriel Martinelli came on for Leandro Trossard and was considerably less disciplined, which isolated Takehiro Tomiyasu against Johnson.

Arteta could be seen giving detailed and persistent instructions to Martinelli to work harder in dropping back, but the visitors couldn’t stem the tide on that side until the Arsenal manager moved to a back five and went into full retreat.

They did enough – just about, leaving Postecoglou to rue his initial team selection.

Match-winner Havertz is sensational as false nine
The match swung on the Van de Ven disallowed goal at 1-0. On another day this match goes very differently, and yet Arsenal were arguably deserved winners simply because they had the best player on the pitch.

Havertz was sublime. This was surely his best display in an Arsenal shirt and perhaps in the Premier League full stop.

“He was sensational in every department today. He wasn’t 100 per cent today, he was ill before the match and was struggling a bit but he still put in the performance that he put in. I thought he was unbelievable today,” Arteta said.

Each sub helped: Richarlison added much-needed aggression up against Gabriel and William Saliba; Yves Bissouma complemented Sarr; and, most important of all, Brennan Johnson’s direct running was a major upgrade down Spurs’ right.

Arguably the biggest reason for Spurs’ late surge was an Arsenal substitution. Gabriel Martinelli came on for Leandro Trossard and was considerably less disciplined, which isolated Takehiro Tomiyasu against Johnson.

Arteta could be seen giving detailed and persistent instructions to Martinelli to work harder in dropping back, but the visitors couldn’t stem the tide on that side until the Arsenal manager moved to a back five and went into full retreat.

They did enough – just about, leaving Postecoglou to rue his initial team selection.

Match-winner Havertz is sensational as false nine
The match swung on the Van de Ven disallowed goal at 1-0. On another day this match goes very differently, and yet Arsenal were arguably deserved winners simply because they had the best player on the pitch.

Havertz was sublime. This was surely his best display in an Arsenal shirt and perhaps in the Premier League full stop.

“He was sensational in every department today. He wasn’t 100 per cent today, he was ill before the match and was struggling a bit but he still put in the performance that he put in. I thought he was unbelievable today,” Arteta said.

One manager adapted, the other didn’t. That was the story of the first hour.

The third, although also from a corner, was initiated by a brilliant turn from Havertz that opened the hosts up to a fast break.

Spurs had committed too hard to the press, leading to the second transition-made concession of the afternoon.

Here we have problems that have followed Spurs for much of the season, exposed repeatedly by an Arsenal team who could identify the weak points all too easily.

One manager adapted, the other didn’t. That was the story of the first hour.

Spurs’ super-subs highlight selection error
Within minutes of coming on for the second half, Pape Sarr’s energy, anticipation, and forward-thinking passing lifted the energy of Spurs, showing why he should have started.

A few eyebrows were raised when Pierre-Emile Hojbjerg and Rodrigo Bentancur were selected as the two starting midfielders, and neither could get a handle on Declan Rice, Martin Odegaard and the dropping Havertz (more on him later).

For Arsenal’s winner, for example, Bentancur was caught ahead of the play as Arsenal broke, while Hojbjerg was easily bypassed by Havertz.

Postecoglou did not – and that is why his team lost.

Raya’s pass accuracy was 57.1 per cent, down from a season average of 75.1 per cent, while Havertz won seven aerial duels, his second-highest number of the season.

It nullified Spurs relatively effectively, albeit Spurs had a few chances in the first half – and scored a goal disallowed for offside – that would have changed things.

But the important point is that Arsenal happily changing their tactics, adapting to the opponent they faced.

Postecoglou did not – and that is why his team lost.

Spurs fail to compromise
Arteta could prepare and adapt for this one because he knew just what his opposite number would do. Postecolgou never changes.

Whereas Raya hit it long to stop Arsenal getting hit by a high press, Spurs played their natural game and sure enough, Micky van de Ven was caught on the ball in his own third, leading to the corner from which Arsenal scored the opener.

Twelve minutes later, Spurs were hit by a classic counter-attack because they had not left enough players back at a set-piece, conceding yet again from a transition.

There is no doubt Arsenal will have worked on exposing this long-term Spurs flaw.

This was Arteta’s plan for stopping Ange Postecoglou’s inverted full-backs.

Here’s how Arsenal won a curious, crucial north London derby ultimately decided by one manager compromising his tactics and the other sticking dogmatically to plan A.

Arsenal compromise their approach in defensive first half
Arsenal’s goals all resulted from the meticulous targeting of Spurs’ tactical vulnerabilities, but before we get to that it’s worth highlighting just how defensive the visitors were willing to be.

Arteta has learnt that flexibility and humility are needed for some of the bigger matches. They held just 28 per cent possession in the first half, primarily because the players were instructed to drop extremely deep when Spurs had a settled spell with the ball.

This was Arteta’s plan for stopping Ange Postecoglou’s inverted full-backs.

Some teams have one midfielder drop into the defensive line, some go man-for-man with the full-backs. Not many of Arsenal’s stature decide simply to crowd the middle in an ultra-defensive shell.

Here is a perfect example of just how busy they made the middle, completely cutting off the inside lanes those full-backs take and forcing Spurs into dull possession in the wide areas.

The second part of the tactic was David Raya consistently hitting long balls up for Kai Havertz to win. It was again a defensive move, and a pragmatic one, designed to minimise the risk of Spurs’ high press.