The Brazil international completed a move to Paris shortly before the start of the World Cup, which took place in his home nation, for a fee of £50 million.
And Mourinho admits that Luiz wasn’t really good enough for Chelsea and only played when others couldn’t. And as a result he believes the squad is much stronger without him.
“Last season he was not regular first choice for us. As a central defender not at all, it was John Terry and Gary Cahill the whole season,” the Portuguese told reporters after Chelsea’s 3-0 defeat to Werder Bremen.
“In midfield, he was a physical guy and gave us important things, especially in the Champions League when [the cup-tied Nemanja] Matic couldn’t play. But this season Matic can play in the Champions League so we don’t lose that physicality.
“The fact we have Cesc Fabregas moves us in a different direction. It’s something that our football needs, and we want to go in that direction.
“David did important things here, was always a good professional and we will miss him as a good guy. But from a football point of view, we believe our squad is stronger this season than it was.”