Something to notice is how the lack of central presence limited Barca’s progression past the second line. Something that always seemed to be a weakness, but under-utilised by teams playing against Barca. https://twitter.com/__eljdp/status/1391062684985090056

Barca struggled to get past the second line of pressure as the half-space receivers were constantly pressed 2v1. This cut off the attackers from the midfield.

And indeed, this is why Messi dropped all the way to the defence and looked to beat a few defenders early hoping it frees some space for players higher up the pitch. But Atleti did well to hold Messi, bar that one time when Messi sprinkled some magic into his run.

In the pictures above, although Griezmann occupies the defence, and looks to pin them, the 2v1 press meant that he was completely isolated.

The only way to progress in this scenario, something that Barca have done often, is to progress through constant switching between the flank and half space. Previously the FB-Messi-De Jong combinations on the right, Alba-Pedri-Griezmann combinations on the left.

More often than not, since Griezmann’s occupying the CBs, we find that the more observed pattern in that on the right, through Messi-De Jong-RB.

But Atletico, did really well in 1v1s and 2v1s. Limiting this kind of progression, driving most of the progressions wide.

Coming back to the main point, when Griezmannn looks to drop deep and aid the midfield, the central occupation is lost, allowing the last line of defence to mark him, and restrict the ball within the Barca midfield itself.