I don’t think Pep will look back on tonight’s performance and single out the defending.
For me, the defining moments of the game was not killing the tie off after the Mahrez goal. We were on top and had at least 3/4 decent opportunities to do so. A second goal negates any potential comeback.
The second big issue was our game management after conceding the first goal. It was a carbon copy of the goal Liverpool scored 40 seconds into the second half in our last PL meeting with them. We have possession from kick off, Eddy kicks it straight to their keeper and they go up the other end and score. I’m fact they almost scored immediately after kicking off in the second half. There definitely seems to be a concentration issue of some sorts.
In situations like that you have to take the sting out of the game. Make a soft foul away from the danger zone or fake an injury for a half a minute. You do anything to disrupt the rhythm.