Chelsea boss Thomas Tuchel believes his side were not "free enough" against Juventus.
The Blues were dealt a modest blow to their Champions League ambitions, losing 1-0 away from home to the Italian giants.
A goal straight from kick off to start the second half from Federico Chiesa decided the largely uneventful contest.
Tuchel told BT Sport: "We struggled to create our own rhythm and intensity because they were so deep and passive. We were lacking runs.
"We were so good in training yesterday and not good enough, not free enough today. I don't know why.
"I felt we were a bit slow and tired, mentally slow, decision-making. That's why it's a strange one to analyse."
Tuchel added: "I think we started not sharp enough. The first 12 to 15 minutes we could have harmed them much more. There was so much space for dangerous balls into the box and ask more questions.
"At this level you cannot concede an easy goal like this in the first seconds of the second half. When you know what's coming and you have defensive organisation like we have, normally it's always possible to defend it. We got punished for it."