Head coach Thomas Tuchel has given his reasons for why Chelsea have suffered defensive problems since the March international break.
In six matches, Chelsea have conceded a total of 12 goals, a further strike coming in extra time against Real Madrid, and it is in sharp contrast to the performances which were being produced up until the middle of March.
After Wednesday's 4-2 defeat to Arsenal, Tuchel was quick to criticise his players for the amount of individual mistakes which were made, and the German was prepared to open up further ahead of Sunday's encounter with West Ham United.
Speaking to reporters at a press conference, Tuchel said: "You don't need to lose this match, not with this kind of performance and not with how the match is running. We have a bad mix of big individual mistakes and a lack of quality in the one-on-one defensive attitude, behaviour, in and around the box. We get punished for it heavily and I'm not so sure whether I have an explanation why.
"The expected goals which we concede since the international break is a bit higher than normal, which is my responsibility and about high pressing, de-pressing, and how chances are created, and to keep the expected goals as low as possible. Since the international break, we conceded 12 goals, which is double the expected goals.
"So, like most things in football, it is a mix of bad luck, circumstances, and the opponent making the very most of what we offer them. We also lack the real determine and attitude in the one-and-one in the box at the moment to really keep the actual goals under the expected goals."
Chelsea head into the fixture with the Hammers having suffered three successive home defeats in all competitions for the first time in 29 years.
