The success of Chelsea's Premier League title campaign is poised to be decided by how well they can continue their remarkable defensive record under Thomas Tuchel -- and therefore West Ham exposed weaknesses on Saturday afternoon that must be quickly eradicated.
This 3-2 defeat at the London Stadium constitutes the first time this season the Blues had conceded more than once in any competition, and it is only the third occasion since Tuchel took charge 11 months ago. It should trigger a kneejerk reaction now given that, in the German's 53 matches at the helm, they have conceded just 29 goals.