The Blues were handed a surprising loss by their London rivals at home on Wednesday.
Asked about the contest and result post-game, Tuchel told BBC Sport: "It was very difficult. Nowhere near the quality of the last three matches and if you don't have this quality you can lose against anybody.
"We are not satisfied. We now have three home defeats with an incredible amount of mistakes.
"We need to find a solution. I don't have one right now. It is completely on us. A number of individual errors you cannot overcome. You cannot give three goals away for nothing.
"I hate losing and losing three times at home is unacceptable.
"I have no interest in praising or criticising individual players today after a team performance like this."
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