I think for Potter champions league is the last chance to prove himself otherwise he can get fired just after losing the game against Real Madrid, that's why I expect to see Chelsea playing with full power against Real Madrid but on the other hand, since for Real Madrid champions league is the first priority I don't think if Ancelotti will let Chelsea win this game easily.
When we are talking about champions league, Chelsea of now under Graham Potter is not can not win real madrid. I'm still wondering how will manage to win real madrid when their performance is not tough . Real Madrid will always win Chelsea as far as this season is concerned.