Tuchel says the Blues were not good enough against Massimiliano Allegri’s men at the Allianz Stadium in Turin.
Chelsea dominated proceedings in both halves but lacked the guile and imagination to cut open the defensive setup of the Bianconeri.
Juventus started the second half sharply and took the lead through Federico Chiesa on 46 minutes and that was enough to inflict Tuchel’s side’s back-to-back defeats.
In an interview with the media after the game, the German tactician admitted his side were not sharp enough in Italy.
"I think we started not sharp enough. The first 12 to 15 minutes we could have harmed them much more,” the former Borussia Dortmund and Paris Saint-Germain said.
“There was so much space for dangerous balls into the box and we could have asked more questions.
"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 and not good enough, not free enough in the match. 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."
Chelsea will be looking to put their two consecutive defeats behind them when they entertain Southampton in the Premier League at home on Saturday.