Thomas Tuchel has been, nearly exclusively, a 3-4-3/3-4-2-1 man with Chelsea. Perhaps the two main reasons for this are that a three at the back is better set up to deal with counters and it has an easier time creating wide overloads in the press and in possession. Obviously it has worked well given Chelsea’s overall record under Tuchel.
Occasionally, Chelsea has gone to more of a 3-5-2/3-4-1-2 shape against certain opponents. The addition of Romelu Lukaku could have triggered a swap to that formation more quickly. Against Arsenal, Chelsea didn’t really break from their 3-4-3/3-4-2-1 but one noticeable change was in how the team pressed with the addition of Lukaku.
Generally, Chelsea has pressed in a 3-1 shape under Tuchel. Against Arsenal, the Blues used both a 2-2 and a 1-3 which indicates another tactical evolution. Lukaku may have been brought in to score goals but the press starts from the striker and the forwards. These changes may not seem like much, but the flexibility the Blues now have sets them up better against all opponents.
Previously, the 3-1 shape would involve the striker pressing the ball carrier while the two wider forwards and a center midfielder (almost always Mateo Kovacic if he’s playing) marking out central passing options. This would force the opposition to play it wide or long. If they played wide, the wingback would immediately start pressing the target and a wide forward would break off in support. If they opposition played long, then a player would step up to win the aerial duel with the target. Either way, the goal was to win possession back as quickly as possible.
Arsenal, playing in a 4-2-3-1, saw Chelsea start with a 2-2 press. The idea is practically the same but it becomes much riskier if another player drops to be a new target in the center. This is likely why, in the opening parts of the match, Jorginho was often found attempting to win the ball. He effectively became the spare man joining the press, but that left gaps for other players to deal with.
Later in the match, the Blues shifted towards more of a 1-3 press. This prevented Arsenal from playing out of the back easily and, much like the 3-1, almost always forced them wide or long. If they opted to go wide, Kovacic would commit to that flank with the wide forward joining in support and the opposite wide forward dropping deeper in case the ball ended up more central.
Regardless of which press Chelsea used, it more or less corralled Arsenal to the same channels if they got all the way through. They would end up behind a wingback but with a very crowded center to pass into for an attempt on goal. Essentially, the press worked as a filter which left Arsenal with only poor options to choose from offensively.
Best of all is that all three of these presses are flexible and could be done with almost any set of players. Furthermore, they also adapt well to a four at the back shape with the primary difference being where the central players will be for possible long balls.
Though three at the back and a central pivot seems to be the non-negotiables for Tuchel, he continues to make tweaks everywhere else based on the opposition and the opponent. These presses were relatively new with the addition of Lukaku, but expect to see them more often regardless as Tuchel’s methods get further embedded into the team.