As with most fiercely contested local derbies, the North London one between Arsenal and Tottenham is rarely a tactically interesting affair. The contest is usually more about passion and commitment than it is about nuanced technical football. The match that has just passed seems to be the exception that proves the rule.
For all that there are some in the Arsenal fan base that look to criticise and even demonise their French coach Arsène Wenger, he certainly deserves the credit for maintaining the form of the Gunners whilst sides around them fluctuate and often drop away for a period of time. Arsenal are consistently challenging at the top of the table.
They play from a now familiar 4-2-3-1 structure with Alexis Sánchez performing a multitude of roles as the lone striker and the German international Mesut Özil floating in space in a traditional 10 role. In most matches between these teams, the system utilised by Arsenal would match up nicely against the 4-3-3/4-2-3-1 hybrid usually preferred by Mauricio Pochettino. In this match, however, the Argentine coach sprung a surprise.
Spurs lined up with a system that almost looked like a 3-4-1-2 system, which caused Arsenal major problems especially when Spurs were able to access the final third of the pitch.
There was little in the way of a surprise from Arsenal as they have used a relatively settled line-up over the course of the last few weeks. Peter Čech remains the undisputed first choice in goal behind a back four of Bellerín, Mustafi, Koscielny, and Monreal.
The only disputed positions within the structure are the two midfield roles in the double pivot. Arsenal started with Granit Xhaka and Francis Coquelin.
The front four were as normal. Nigerian youngster Alex Iwobi has impressed on the left, and on the right Theo Walcott had found a rich vein of form. Özil and Sánchez would provide the attacking thrust in the centre.
The Spurs line-up also had a familiar feel despite the change in system. The back three consisted of Kevin Wimmer, Eric Dier and Jan Vertonghen, while Kyle Walker and Danny Rose provided width on either flank. Victor Wanyama and Mousa Dembélé played centrally with Harry Kane, Christian Eriksen and Son Heung-Min providing an attacking threat with a fluid front three.
Arsenal struggle to penetrate Spurs structure
In the opening exchanges of this match, Arsenal found it difficult to get to grips with the Spurs structure. In the centre of the park Coquelin and Xhaka struggled to pick up the staggered midfield two of Dembélé and Wanyama, with the former especially finding time and space to dictate the tempo for Spurs.
In their defensive third, the close connections and interchanging of positions from Son, Kane and Eriksen were forcing Mustafi and Koscielny to constantly change position and pick up different players moving in and out of their zones.
It was in the attacking third, however, that Arsenal struggled most often as the use of Sánchez as a false 9 made it extremely difficult for the Gunners to penetrate the Spurs box.
One of the key aspects of Arsenal’s attacking success so far this season has been their capacity to create overloads into space for their front four to flood the opposition’s box. Against Spurs and their back three, the spaces on the pitch in the final third was altered by Spurs’ use of the back three. Arsenal struggled to adapt.
This still was taken in the first half of the match and as you can see Arsenal are actually spaced nicely across the final third of the pitch, with advanced players occupying four clear vertical lanes on the pitch. The issue, however, is that they have no player directly challenging the Spurs back three.
In this instance, the only realistic way that Arsenal are going to threaten the Spurs goal is via a long shot from distance or an overload around the back three.
Against a three-man defence Arsenal should have had the capacity to play into the space in front of the defensive block but time and time again they failed to provide vertical runs off the ball that would have enabled more penetration of the box. With Sánchez and coming deep too often, Spurs were relatively comfortable in their defensive phase.
From time to time Arsenal were able to create gaps in the Spurs defensive structure to play through. Here, with the ball in the wide area, the Spurs defensive line is stretched across the pitch and gaps start to appear centrally. The deeper starting position of Özil is perfect for making the late run towards the box that can counteract the defensive stability of a back three. As the ball is cut back first to the supporting midfielder and then centrally to Özil, he is able to get a shot on goal.
With their 3-4-2-1 system, there were some interesting aspects to Spurs’ play in the build-up phase and in more direct attacking actions. Unlike the more traditional four at the back systems there are some really nice instances of balance across the width of the pitch.
One of the main benefits is fielding a back three is the flexibility that it gives you in the build up phase. Here the man in possession has three comfortable passing options should he wish to move the ball on, and two which are more tenuous but still possible.
As a rule the larger the distance that you are trying to pass the ball over the higher the chance that the pass will fail. That’s why players come towards the ball to make the pass easier for the man in possession. In this instance there are a number of options to allow Spurs to play through the Arsenal press.
The interchanging three-man front line for Spurs was difficult for the Arsenal defence to pick up properly. Danish international Eriksen was nominally playing behind Son and Kane in the 10 position, but each of the three players moved across the front line seemingly at will.
By attacking with three central players in this manner, Spurs were opening spaces in the wide areas for the wing-backs to advance forward.
In the photo above the ball is switched out to Kyle Walker who advances down the clear vertical lane on the outside of the pitch and is able to play the ball into the box towards his advancing strikers.
In this example, the movement of Kane out to the right has actually pulled Arsenal centre-back Laurent Koscielny out of positon. Son and Eriksen are in the central positions but both have taken up areas between the lines of the Arsenal defence and midfield. As the ball is swung out to Danny Rose in the wide left area, the defensive structure of Arsenal is completely stretched.
Arsenal switch defensive emphasis
In the second half, despite the match still being end-to-end and either team having enough chances to win it. Arsenal altered their structure and started playing more reactively in order to counter the central threat being posed by Spurs.
As Spurs are building up their attack and looking to enter the middle third of the pitch, we see a much more structured defensive block from Arsenal with Özil even dropping back to a more traditional 8 position.
Earlier in the match, Özil would constantly look to join Sánchez in a two-man press in order to disrupt the Spurs build-up. Now he was dropping in to prevent Spurs from easily playing through the lines and into the central attacking areas of the pitch.
This was a fascinating tactical battle. Despite being accused by many Arsenal fans of being unwilling to change tactically, Wenger showed in this match that he could still react to specific threats being posed by the opposition.
With Harry Kane still feeling his way back from injury, Pochettino was intelligent enough to ensure that he had close support from Eriksen and Son in order to minimise the amount of work he would have to do in the final third.
Spurs have the personnel to switch to a back three system on a permanent basis and it will be interesting to see whether this becomes a regular switch.
By Lee Scott. Follow @FMAnalysis