Unai Emery’s tenure with Arsenal was a lot like a rollercoaster ride. There were multiple ups and downs that no one saw coming.

One of the pinnacles of Emery’s tenure came on April 1st of this year, when Arsenal climbed to 3rd place in the league table. Everything seemed to go the Spaniard’s way at that moment but, like those roller coasters, Arsenal accelerated downwards at lightning fast speed after reaching their peak. The club failed to qualify for the Champions League after a late collapse and their poor form carried over to this season.

Emery’s demise as manager of Arsenal did not happen for one sole reason. Instead, there were a multitude of reasons as to why he failed to get the very best out of his team, which provided for grounds on a justifiable case to sack him this early in the season. The players and coaching staff will now move on without Emery, but there are several lessons to take away as to why the board had to ultimately come to this decision.

Lack of a team identity

The term “identity” has increasingly become a buzzword in world football. For instance, Ernesto Valverde has come under heavy criticism for his inability to embed to an attacking identity with Barcelona. And more recently, Mauricio Pochettino was sacked by Tottenham after them looking like a shell of themselves over the opening four months of the season.

With Arsenal under Emery, there was also an extensive amount of team identity issues. He had problems establishing an identity from his very first game with the club, which held the team back from playing up to their strengths on a game-by-game basis.

From a tactical perspective, what exactly was Arsenal under Emery? Were they a possession-based team with a knack on breaking down low blocks, or were they a team that placed a heavy emphasis on counter-pressing and creating goal-scoring chances on quick transitions? It seemed as if Emery did not even know the answer to this question, nor did he ever figure out what truly worked best for his side.

This season, Emery employed a variety of formations to see what gave the team the best results with the personnel at hand. As of late, he operated his team under a 3-4-1-2 setup, which used three centre-backs and a central attacking midfielder hovering in behind the two strikers. This formation gave the team a luxury of building up play from out wide, with their fullbacks or from inside through the central attacking midfielder -- a tactic which Emery clearly ignored due to their stubbornness on not occupying space from the center. Needless to say, this setup evidently did not generate the attacking results he had hoped for.

However, his formation tinkering was never the lone cause for the team’s struggles to implement a free-flowing tactical system; it was also on the team’s approach. For instance, over the past month, the team had clear positioning issues that limited the double pivot midfield from building through the center. There were clear miscues when it came to knowing just when to trigger off-ball runs in behind opponent’s midfield and defensive lines, as was evident with the team’s lethargic attacking sequences. As a result, the gaps in Arsenal’s setup often left Aubameyang and Lacazette with little to no service in the final third.

More importantly, and fatally to his Arsenal tenure, Emery seemed to overthink just how he wanted his team to orchestrate play, in both the attack and defense.

Through four months of this season, he had developed the habit of adjusting to opponent’s tactics, rather than forcing them to modify their own tactical setup to counter what Arsenal wanted to do. Look, for example, at how they performed in their 1-0 loss against Sheffield United in league play. As expected, Chris Wilder’s side played in a deep low block when out of possession. Yet even with that setup, almost daring Arsenal to attack, Emery was more conservative in his attacking approach, due to his unwillingness to position his double pivot of Granit Xhaka and Matteo Guendouzi closer to the box and in between Sheffield’s midfield lines.

For some reason, Emery played right into Sheffield’s tactic of keeping players away from positioning or making free runs into the box. Arsenal had previous success in pushing high up the pitch, but this was nowhere to be seen against Sheffield. It becomes impossible to establish a rigid team identity and play style when the manager is constantly making significant tactical changes on a game-by-game basis.

In world football, a team’s identity does not just revolve around the tactical aspects of the game. “Identity” is an umbrella term that also coincides with how a unit responds to adversity, or their willingness and ability to finish games. One could look at Liverpool’s recent run of games and, although they may have benefitted from several VAR calls, their strength in not moving away from their team identity of gegenpressing and playing through the center has been the catalyst to their ability to keep their unbeaten run in league play this season. In contrast, look at Arsenal’s last five games and how they resort to passive attacking tactics of merely sending in aerial balls to the box in order to create any goal-scoring chances.

Intensity, resilience or passion was hardly ever displayed in Emery’s final games with the club.

Prevalent defensive issues

If there was one component of Arsenal’s play that constantly frustrated the fans, it was their array of defensive problems. Through 13 Premier League games this season, Arsenal are the only team in the top 10 with more goals allowed (19) than goals scored (18). Had it not been for the heroics of goalkeeper Bernd Leno, their defensive numbers might have been historically atrocious.

Blame goes both ways when it comes to the team’s leaky defense.

For one, Emery did a dismal job of setting his team up to maintain an efficient high line. It seemed as if there were several occurrences per game where an opponent’s forward would make free runs against Arsenal’s defensive line. And to make matters worse, Arsenal’s defenders - in either a defensive back two or three - had the nagging habit of leaving their lines in unnecessary moments.

For example, see here how Sokratis comes off of his defensive line to attempt a soft press against the Southampton ball carrier. There is absolutely no need for Sokratis to drift this far off of his line, considering Guendouzi and Torreira are already overloading on the left side of the pitch. But the most crucial aspect was how much open space Sokratis left behind in the defensive line. Fortunately, no Southampton player recognized the sequence unfold as no one made an off-ball run into the open patch of space.

As mentioned, blame goes both ways and Arsenal’s defenders must take partial responsibility for how poor they defended as a unit. With defending, there are three keys to employ a dominant defensive setup: communication, positioning and box awareness. But throughout the season, it looked as if Arsenal’s defense lacked all three of the aforementioned keys and as a result, they had very little chemistry on the pitch.

This sequence in particular lacked all three keys. There is clearly no communication; all six Arsenal defenders in the box are ball-watching. The positioning is abysmal, as four Arsenal players are nearby the Leicester ball carrier. And with box awareness, no defender recognized the wide open Ndidi and Maddison in the box. The result of this sequence was a high percentage shot from Ndidi that hit the woodwork.

Arsenal’s defense under Emery this season was not historically bad, but they are a defense that ranks among the relegation teams in the Premier League. As shown below, Emery’s side had an extremely difficult time in limiting opponents attacking production in open play. (The open play goals and shots allowed does not include penalties, corners, set pieces or direct free-kicks).

In total, Arsenal have allowed 11 open play goals and 158 open play shots through 13 Premier League games. The 12.2 open play shots allowed per game ranks near the bottom of the league this season. Arsenal must be thankful they have Leno in goal.

Disorganized pressing structure

One key tactical aspect that Emery wanted to implement was an organized and effective pressing structure.

How a team presses is one component that separates a team merely fighting for a top six spot in the Premier League from one striving to win the league. It is not just about pressing a ball carrier and limiting the available space for the opponent, but it centers more on the underlying goal of successfully winning back possession. Of course, there are risks with pressing in numbers. As teams like Manchester City and Liverpool have shown over the past couple of years, an organized setup when triggering a press can go a long way in preventing the opponent from finding ways to counter on a quick transition in open space.

For the most part, Arsenal had a relatively decent pressing structure under Emery. Last season, Arsenal recorded 9.47 passes allowed per defensive action in opposition half (PPDA) according to Understat, which ranked 3rd in the Premier League. This season, Arsenal have marked at a fair 9.71 PPDA, which ranks 7th in league play. While PPDA is not the sole indicator to determine how well a team presses, it illustrates Arsenal’s capability to win back possession at a moderate rate.

The problem, however, was Arsenal’s constant mental lapses and poor positioning when pressing. Time after time, it seemed as if the players did not trust one another, and seeked to take matters into their own hands. At times when this would occur, it opened up space for opponents to move into considering Arsenal often moved of their designated pressing area.

This is exhibited here as Guendouzi makes a trivial attempt to press the Southampton ball carrier. The problems? Two Arsenal players are already surrounding the space near the ball carrier and due to Guendouzi’s movement away from his area, Southampton are able to counter the Gunners’ press in the middle third by finding a wide open unmarked player.

This falls on Emery. Of course, managers want their team to be aggressive in pressing to win the ball back as soon as possible. But there is a stark difference in being aggressive and reckless. More often than not, Arsenal’s seemed to counter their own pressing structure due to the players’ overaggressive habit of constantly moving out of their own area. In essence, it became feasible for opponents to periodically work their way into the final third against Arsenal’s press.

When it came to addressing the issues on defense and pressing, Emery should have taken a page out of New England Patriots head coach Bill Belichick. The six-time Super Bowl winning-coach is synonymous with the quote “Do Your Job,” which calls for players to not only perform at the highest level but also to handle their own assignments. This essentially extends to having each player only take care of the duties they were assigned to cover.

Had Emery instructed his players to stop attempting to do too much on the pitch and only worry about their own designated responsibilities, Arsenal’s pressing and defensive setups may not have been all over the place. There may not been multiple unnecessary double-teams on a ball carrier or movements out of space in order to assist a teammate who did not need any help at all in pressing.

Of course, there are other reasons Emery failed to succeed with the Gunners. From playing talents out of position, to not playing Aubameyang or Lacazette as a deep-lying forward in two striker formations, it ultimately became a whirlwind of a mess to handle.

From a glass half full perspective, there were a couple of positives to take away from Emery’s run with Arsenal. The club did start out 2018/19 with an amazing 22-game unbeaten run in all competitions, and also completed a run to the Europa League final. More importantly, he provided a platform for several of Arsenal’s youngsters to display their potential and also gave them an opportunity to show why they are deserving of a first-team spot.

But in the end, it became crystal clear Emery was not the right man for the job. He will now likely return to Spain and wait for any managerial spots to open up in La Liga. Meanwhile, Freddie Ljungberg takes over, with a hefty mess to clean up.