The Blues will seek to bounce back against Champions League opponents Schalke.
"When you win a lot, you cannot forget why you win," Mourinho said.
"You cannot think that you win just because you have a nice shirt or you are on a good run or you are in a lucky moment.
"When you think that, you are in trouble. You never can forget why you are winning matches and maybe we forgot.
"I hope now they don't forget why they won a lot of matches and why they lost against Newcastle. If they have that clear in their minds we are fine."
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