Chelsea produced a last-gasp 2-1 victory over Atletico Madrid, with Michy Batshuayi scoring the winner deep in stoppage time after approaching as a second-half change for Alvaro Morata.
Luiz conceded a penalty within the first 1/2 and Antoine Griezmann took complete benefit, slamming his spot kick house.
And former Leeds defender-turned-pundit Mills thinks the loss of a robust presence within the dressing room like Terry may well be affecting Luiz.
“I think he has become a little bit rash. We didn’t really see that from him last season,” Mills instructed BBC Radio five are living.
“It may well be to do with John Terry no longer being across the position and having a phrase with him telling him ‘calm yourself down and play your game’.
“Last season Luiz used to be good, however he were given a unnecessary purple card towards Arsenal and he gave away a penalty towards Atletico.
“We noticed what he can do going ahead, for instance the cross for Morata however we additionally the see darkish facet of him.
“He can provide away foolish fouls and passes to the opposition. That is when he can transform a legal responsibility and folks get on his again.”
Antonio Conte’s males now best Group C after two wins from their two crew video games, and feature back-to-back ties towards Roma to look ahead to.
Chelsea go back to Premier League tasks once they host Manchester City on Saturday (five.30pm).