During the opening stages, Chelsea had difficulty moving the ball forward through Arsenal’s high and compact block. Özil was always close to Kovačić to restrict him from collecting the ball and driving forward through the lines, while Arsenal’s front three let Chelsea’s back three have the ball, but pushed up onto passes made wide and back inside, blocking the passing lanes. This left Chelsea’s backline often taking time on the ball waiting for options and drawing pressure onto themselves, which led to rushed clearances or long passes. Emerson dropping deep to collect the ball under close pressure would often see Arsenal recover ball instead, and many attempted long passes were lost as Arsenal covered wing-backs with full backs out quickly and central midfielders dropping back to cover. Chelsea’s only successes with the ball came by playing off Abraham and by Willian drawing fouls to win free kicks and move up the pitch.
Chelsea had further trouble when trying to press Arsenal, where they would find themselves in a 5-2-3 trying to press from the middle and having to open themselves considerably to close down the ball. When pressing from a back five, like with Conte, it is important to push up on the sides and involve the nearside wing-back, otherwise the team is very open and defending in a much more individual than collective fashion.
Given Chelsea’s problems with pressing, Arsenal could advance through Özil in midfield and the final third, play off of Lacazette, and use their speed to go on the outside of Chelsea’s backline to advance and get behind on the wings — going on to take the lead from a corner.
3-4-3 to 4-3-3
Chelsea’s change of Jorginho on for Emerson (switching to 4-3-3) made a big difference in the game for multiple reasons. With the ball, Arsenal could no longer press inside from the wings as they had earlier on (wingers on fullbacks) and Özil would press onto Jorginho or one of Chelsea’s central defenders. Kanté and Kovačić could push higher up and open up midfield much more with their positioning, as well as being able to collect the second balls when playing long diagonals from the back. For the latter, long switches to Willian (now on the right wing) made a big difference with Kanté recovering the ball and Willian able to create individually or hold onto the ball from the right wing, while Azpilicueta made runs behind on the left. Chelsea gained position, but didn’t create many chances to equalise.
Chelsea’s change also saw improvements in pressing, where they could now match Arsenal’s numbers comfortably and press in a much more compact and collective manner, recovering the ball high and stopping Arsenal from building attacks as they had during the opening of the match. Arsenal were now pushed back to defend their own half and deep positions (unable to defend high and advance to the final third with possession), but would go into halftime with their one goal lead.
Chelsea continued to maintain possession and play high up during the second half, while Arsenal were unable to find a solution to Chelsea’s switch of formation during the first half — unable to press high or maintain the ball to build attacks. Unable to play through Chelsea’s high pressing, Arsenal would switch to playing long from the back and revert to defending deep with numbers, and looking to counter attack with speed.
Chelsea managed to control many of Arsenal’s attempted counters by winning the ball high up or by committing fouls to stop dangerous situations progressing. But with the ball, Chelsea still had difficulty breaking Arsenal’s deep defending down. Given Arsenal’s deep defending, Chelsea would now not play so many long balls to the wings and instead looked to use short passes and combinations on the wings. But both Arsenal’s wingers and central midfielders would join the wings in support of the fullbacks to reduce the amount of crosses into the box, as well as make clearances when the ball was put into the box.
The turning point came through Leno’s mistake to allow the ball go over his head for Jorginho to pass the ball into an empty net, followed by a quick counter attack for Chelsea to go on to take the lead and see out the game with a win.
Arsenal made the better start to the game, pressing Chelsea well, recovering the ball, and playing through Chelsea’s attempts to press high — creating opportunities to score and taking the lead. Chelsea’s change to 4-3-3 with the introduction of Jorginho for Emerson made a big impact on Chelsea’s capacity to match Arsenal while pressing, provided solutions for building from the back, and pushed Arsenal back to defend deep. Arsenal’s deep defence remained strong until the final stages, where an individual mistake and an excellent counter attack by Chelsea made the difference.