Chelsea boss Antonio Conte offered no excuses after defeat to Roma on Wednesday night.
Chelsea were thrashed 3-0 in their Champions League encounter through goals from Stephan El Shaawary (2) and Diego Perotti.
Afterwards, Conte conceded it had been a "bad night".
He lamented: "When you lose 3-0, it means it wasn't a good performance. Our first half was good, we created many chances to score, but to be 2-0 down was unfair.
"But in the second half, it was a really bad performance. Roma showed more will to fight and more desire to win the game. I'm very disappointed with our second half. For this performance, we all have to take responsibility.
"When you concede three goals, you must be worried. It means something doesn't work.
"It's very difficult now, but we have to analyse the game. We need to work on the tactical aspect. We are working less on this aspect this season. We have to look at ourselves. Tonight was a bad night for us. Just one night, I hope."