The north London side made it back to back wins in the Premier League for the first time this term when they sealed a 3-2 win at Cardiff in the top flight on Sunday afternoon.
Unai Emery has been tasked with steering Arsenal back into the top four in the Premier League this season after the Gunners missed out on a top-four finish in their last two campaigns under Arsene Wenger.
The Gunners lost their opening two Premier League games to Manchester City and Chelsea FC but wins over Cardiff and West Ham United have helped to restore some positivity around The Emirates.
The main target for Arsenal this season will be finishing in the top four, but Petit feels that the Gunners have no chance of Champions League qualification unless they improve their defending.
Speaking in an interview quoted by the Daily Star, Petit said: “Arsenal’s defence is still a long way from the level needed to compete with the top four teams in the Premier League.
“We saw it again against Cardiff. It is a recurring problem, that dates back years with Arsenal.
It has never been fixed, neither by Unai Emery, nor Arsene Wenger, nor the players out on the pitch.
“Pierre-Emerick Aubameyang and Alexandre Lacazette can score 40 to 50 Premier League goals a season between them if they are picked to start matches.
“But even with these two, Arsenal won’t be able to finish in the top three if they don’t sort out their defensive problems.”
Arsenal will return to Premier League action after the international break when they take on Newcastle United away from home.
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