Recording just one clean sheet in three Premier League games thus far, Luiz has insisted defensive improvement is key if they want to challenge for the title this season.
"We have to [bring the number of goals down]. I think if you concede a lot of goals you cannot fight for the title so this is one main thing we have to think about and try to reduce and try to make the team stronger," he told UK media.
"It is not just about me, it is not just about the defenders, it is about the mentality of the team.
"I think the team already did great against Newcastle, did great against Burnley to understand the kind of game we were playing for," David Luiz said
"We were clinical in Newcastle with one clear opportunity we scored and didn't concede.
"With Burnley, we were clinical to understand the game is always to play first ball, second ball, fighting. They tried to score with free-kicks and things like that and we did amazing and [against Liverpool] I think it could be a different game if we scored [first] but we did not and so this is about football.
"Football is like that. Every week is a new history and we have to try and learn and improve our game."
David Luiz joined the Gunners from Chelsea for a reported fee of £8 million after featuring thirty-six times with 3 goals for the Blues in the Premier League last season.
Arsenal will host their city rivals Tottenham Hotspurs at the Emirates Stadium on September 1.
