Thomas Tuchel has claimed the Stamford Bridge pitch was partially to blame for Wednesday's loss to Arsenal.
"To say the pitch is difficult to play here it maybe sounds like an excuse, but it is a very, very difficult pitch that we have here," said Tuchel. "It's not in our favor. The ball bounces very awkwardly in front of Andreas when he wants to play this ball.
"But still, we had the same mistake against Real Madrid that cost us the next round of the Champions League, and this one cost us the next match. I can't remember when we got two goals like this.
"We conceded seven goals with Toni [Rudiger] against Brentford and Real Madrid, that answers the question. It's not about individual players. A defensive performance is a team performance, and an offensive performance is a team performance. You need to have the tactics right, which is doubtful I had this right, and you need the team selection right, again it's doubtful I had this right.
"Then it's a game for the players. They get full praise when they do it when they did it for the last three matches. And they have to face the reality that it's impossible to win matches if you make this amount of mistakes of this calibre. It's simply impossible. I don't see it in any other matches, but I see it now in consecutive matches of our games, and it has to stop."