Luiz, who joined Paris Saint-Germain in a reported £50 million deal earlier in the summer, captained his country in the absence of the suspended Thiago Silva.
But the host nation found themselves 5-0 down before half an hour had been played on a nightmare evening in Belo Horizonte, with Luiz suffering a torrid time in the centre of defence.
Blues boss Mourinho told Yahoo!: "I don't think it's fair to separate a player from the team, because the team was really bad.
"David made mistakes? Yes he did. But Dante made mistakes, Marcelo made mistakes, Fernandinho made mistakes. The team as a team made mistakes. So I don't think it's fair [to pin most of the blame on Luiz]."
Mourinho also said he felt sorry for Brazil, who are coached by Luiz Felipe Scolari -- a former Chelsea manager who lasted for only 36 games in London before being replaced by Guus Hiddink.
"I think all of us are feeling really sorry for them because it is a historical moment -- a moment that we will remember forever," he said.
"In 50 years, our kids will know that Brazil lost at home against Germany 1-7. From my point of view, from the professional point of view, it's heartbreaking and I'm really sorry for them."
Broken-hearted Brazil bow out
The ESPN FC crew review Brazil's stunning exit and explain how Germany were able to exploit a vulnerable Brazilian back line.
ESPN FC show 7/8
The FC crew break down Germany's demolition of Brazil, preview Netherlands vs Argentina and discuss the latest transfer news.