Southampton made their intentions clear from the start of the game with a very aggressive approach. Their front three were narrow (playing on the inside of Chelsea’s fullbacks) so they could push up onto Kepa and cover his short passing options. The wide central midfielders would shift to the side of the ball to cover the fullback, leaving the far side fullback as the escape route to break pressure.
Despite Southampton putting themselves in good positions to put pressure on Kepa, force Chelsea to play long, and create situations where any mistake would give them a clear chance to score, Chelsea limited the errors they made with the ball in buildup, recovered quickly in situations where they lost the ball, and even played through the pressure on a few occasions.
Chelsea were also aggressive defensively from midfield, and created the same problems for Southampton with the ball at the back. Southampton had a lot more problems dealing with this than Chelsea, especially when playing back to Gunn and attempting to clear the ball — many clearances not reaching the halfway line and providing Chelsea a platform for short counter-attacks. When recovering the ball with high pressing, Jorginho was instrumental to starting counters by playing the ball forward quickly — including for both of Chelsea’s first two goals.
The fullbacks would come into the game for both sides when the ball moved forward into midfield and the final third. Alonso overlapping while Hudson-Odoi moved inside (followed there by Valery) created space on the outside for Alonso to receive the ball in the buildup to Chelsea’s third goal, while Valery would also find a route behind Chelsea’s backline by underlapping Redmond from a throw-in (Alonso wide and close to Redmond) and carrying the ball through to find Ings inside the box — quick movement from him to get ahead of Zouma for the finish.
The second half saw a number of stoppages for fouls and the ball going out of play break up the flow of the game. When Chelsea were able to attack, the attacks were mostly quick counters leading to quick shots. Breaking Southampton’s pressure often just led to fouls or clearances out of bounds, while Southampton would also win a number of fouls after turnovers to stop Chelsea’s attempts to recover the ball high up.
Chelsea’s changes were made late in the half, and two of the substitutes would combine well to create and score Chelsea’s final goal, where Batshuayi left the middle to loop around the back of Pulisic, losing the defenders, getting a free run for the return ball, and finishing — Pulisic showing quick feet in the process to hit the pass early behind Southampton’s backline.
Chelsea dealt with Southampton’s high pressure more efficiently than Southampton were able to deal with Chelsea’s, which provided Chelsea with counter-attacking opportunities that lead to them scoring twice in the first half. Both sides were able to utilize advancing fullbacks to move into good positions and create chances — Alonso (losing man) and Valery (carrying ball through) both set up goals during the first half. The second half consisted of a lot of stoppages for fouls and the ball going out of play, but Chelsea still created chances to score, both from counters and by playing through Southampton’s pressure in midfield, before rounding off the night with Batshuayi and Pulisic combining for a fourth goal.