Chelsea started the season with three left-backs. Somewhat comically they had more players in that position than they did fit first team strikers.
After the first game it became relatively obvious that actually Mauricio Pochettino considered there to be four after Levi Colwill was selected for the role in an asymmetrical 4-2-3-1 shape. That alone divided opinion with debate raging on over whether or not it was a dysfunctional 3-5-2 but it didn't take long before the true shape was apparent.
The choice to move one of the world's best young centre-backs and to park him out wide despite no previous senior experience there has attracted criticism and been blamed for the underwhelming results. The reality is more that Chelsea were still able to create chances as consistently as the top sides in the league and defend their box generally as well as their rivals too.
The results, which largely hinged on poor finishing and lapses in defensive concentration, have come in spite of Colwill at left-back and Ben Chilwell further forward, not because of those choices. To be working as one attacker down and still doing the majority of things well is actually more impressive.
Now, though, there is a more serious re-think needed. Pochettino had already started to move away from the exact system that he started the season with — which was already markedly different from the one used in pre-season — after playing Mykhailo Mudryk at left-wing instead of Chilwell. That all changed on Wednesday night.
Chilwell started his first game of the season at left-back but the defence he was with couldn't have been stranger. Axel Disasi, once more selected in the right centre-back slot, was the only man playing the role he had been used to this term.Read on football.london