If you're going to play in 20 minute spurts then you need to have a good defensive plan for the recuperation period. We clearly don't - not yet at least.
This.
It isn't possible or sustainable to maintain all-out attack for 90 minutes, at least certainly not against most PL level opposition.
The best teams use the recuperation time proactively, slowing the tempo of the game and controlling possession, frustrating the opposition and causing them to tire due to constantly chasing the ball.
We aren't very good at that part of the game.

