It would be unfair to blame Edouard Mendy for Chelsea’s defeat against Real Madrid – the team were were poor in attack and in defence, and the Blues were already two goals down against Real Madrid when the goalkeeper made his mistake.
So Thomas Tuchel was right to defend him, despite the colossal error against Los Blancos. He pointed out that playing as a goalkeeper in a modern team exposes you to making big mistakes like that – although he did admit that the stopper knew he could have done better in that moment.
You can see the manager speaking in the clip embedded here, with this answer coming after 12 minutes:
I want chelsea players to levae fear and train well so that they will be able to defeat Real-Madrid second lerg.