The 26-year-old was selected on the right side of the Gunners' defence for Saturday’s 1-1 draw in the north London derby, and he gave away the penalty that saw Harry Kane draw level for Spurs in the second half.
Petit, who won the Premier League title with Arsenal in 1997/98, criticised the defender’s clumsiness but also admitted that he harbours doubts over Unai Emery’s leadership of the team.
"I was surprised to see Mustafi picked for that game, because he is after all the king of blunders," Petit told RMC.
"Even though it shouldn't have been a penalty because there was an offside, it's Mustafi who gives away the penalty again."
He continued: “Emery steers the ship well but there are certain things in his management style that concern me. I hope I'm wrong."
The result leaves Arsenal in fifth place in the Premier League, one point behind Manchester United in the fourth and final Champions League spot.
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