Emmanuel Petit says that Arsenal must be wary of David Luiz's unpredictability ahead of the North London Derby.
The Brazilian international arrived from Chelsea for a fee of £8million during the summer transfer window and has already established himself as a first team regular at the Emirates.
While Luiz is undoubtedly a player of quality, the former Gunners midfielder said that Unai Emery must be realistic with his expectations from the defender as he is prone to 'individual errors'.
Speaking to Paddy Power News, he said: "David Luiz is like Dr Jekyll and Mr Hyde, like Hulk and Bruce Banner. He can do great things in terms of leadership and aggression, spirit and mentality.
"We all know his warrior qualities, but we also know that he be off his game for many reasons, and that he takes many risks when it comes to positioning and possession.
"You don't know what to expect from him at any given time.
"He was brought in during the closing stages of the transfer window so he's a good bargain, but the reality is that if he plays 40 games in a season, he'll make many individual mistakes."
Emmanuel Petit was speaking exclusively to Paddy Power News. You can read more HERE.
