Unai Emery's have dropped to fifth in the Premier League standings after their second league defeat of the season, and sit ten points behind league leaders Liverpool.
But Luiz has insisted there is no need to panic ahead of Sunday’s meeting with Crystal Palace at the Emirates.
“We have to be honest about what went wrong, but we also have to be calm,” the 32-year-old told Sky Sports.
“It's only our second defeat this season. We are doing many things well. We have to keep believing in our philosophy, we have to keep believing in our team, which is the best way for us to improve.
“Football is about the end, not the beginning, so let's see how we finish at the end of the season in May.”
Arsenal on Sunday face a Crystal Palace side who have made a strong start to the season and sit just a point behind their hosts.
And Luiz has emphasised the importance of a victory after Monday night’s setback.
“We have to win, we always have to win,” he added. “If you want to achieve big goals, you have to think about winning, winning, winning. It'll be tough against Crystal Palace but we want the three points.
“I want to win titles with Arsenal, that's why I'm here.”
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