Chelsea and Atletico Madrid squared off against each other in the first leg of their UEFA Champions League round-of-16 encounter on February 23rd, 2021. The game was always going to be a tight affair given Atletico’s inclination towards defending and Chelsea’s not-so-potent attack under Thomas Tuchel.

How they started

The two teams lined up very similarly, with the only difference being in how their forwards lined up on paper. The Premier League side went with a 3-4-2-1 formation (as seen in the image below) with wing-backs in Marcos Alonso and Callum Hudson-Odoi.

Atletico, too, went with a 3-man centre-back partnership with two wing-backs supporting them. This is also consistent with how they have been playing for most of the season. Renan Lodi occupied the left wing-back spot with the versatile Marcos Llorente playing as a right wing-back.

The La Liga outfit were maintaining their shape at the start of the first half. Chelsea were willing to pass the ball around the back, and Atletico were not scared to push men up the pitch and press Chelsea aggressively. This also led to some exciting goal-mouth action.

However, for the majority of the game, Atletico went with a 6-3-1 flat defensive line despite occupying a 5-4-1 line at some stages of the first half. This 6-man defence, as you can see in the image below, consisted of left wing-back Lodi (white circle), with Angel Correa (black circle) falling back from a right-forward to play as a right-back.

Marcos Llorente (yellow circle) would drop in the defence to make a 4-man centre-back line. This is where the left-forward, Joao Felix (red circle), would play as a third central midfielder.

Due to Chelsea’s 3-4-2-1 formation, the creative onus fell to Matteo Kovacic and Jorginho, who were the two central midfielders. This was good thinking by Atletico as the Chelsea duo have a very poor xA90 (expected assists per 90 minutes) so far this season.

How Chelsea responded and how the goal came

Nothing was coming from playing their on-paper formation of 3-4-2-1. Mount, Werner, and Giroud were interchanging positions but there was nothing happening in the midfield.

This is when Kovacic started playing further up in the Atletico half. As visible in the image below, this created space for him in between the lines of Atletico defenders and midfielders.

To supplement this, Chelsea also made Cesar Azpilicueta, their third centre-back, push much higher into the midfield to offer numerical support there. This is visible in the touch-map of the Spaniard below.

This helped Chelsea combat Atletico in midfield and get numbers up front. However, the 6-3-1 formation was proving impossible to counter. Hence, Chelsea started concentrating their play on their right flank, drawing defenders there to give space on the left flank.

Atletico’s deputizing right-back Correa (marked red) was being dragged out of position a bit more often in the second half. This gave Marcos Alonso (marked white) space on the left-hand side, where Chelsea’s chances started to come from.

This is also what led to Chelsea’s only goal of the game. Atletico’s right-back (marked white in the image below) was dragged out of position due to Simeone’s side wanting to be adventurous. Chelsea played the ball out quickly and Marcos Alonso had time to cross.

In the image below, you can see Alonso bombing forward and Atletico failing to get a man behind him. His cross found Giroud somehow and the French striker finished emphatically.

Chelsea then defended in a 5-3-2 (see below) in the closing stages of the game, with the formation shifting to 5-4-1 when they were pegged back a lot. It was a proper park-the-bus performance after getting the lead, a tactic Atletico themselves deployed from the first minute despite being at home.

Verdict

Chelsea had the onus to break down Atletico. Simeone was super defensive in his tactics and Chelsea had to find ways to create.

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They did this by making space for Marcos Alonso, whose cross resulted in the only goal of the game. Chelsea now have an invaluable away goal to take into the home game, one they deserve after taking on a resolute Atletico side that was hell-bent on keeping a clean sheet.

(All match footage taken from official UEFA match highlights from BT Sport)