Costa presses Luiz and thiago silva, they pass around and hold possession. Ibrahimovic presses cahill and Ivanovic, they hoof the ball away.
Willian in presses Verratti and thiago Motta, they spin round him and pass to another player. Matuidi presses fabregas and they fall down without any strength or mobility of xavi and Verratti to escape pressure.
That's the difference between the two teams and why we were under pressure in the second half once PSG started pressing through the middle of our team. The number of players that can't hold ball under pressure in our team is criminal for a top team.