Mustafi has struggled to justify the Gunners's £37m investment, with a series of mistakes costing him a place in Unai Emery's side.
World Cup winner Petit labelled the German defender the "king of blunders", with the 27-year-old rejecting a move away this summer.
"I am self-critical enough to see that I made those mistakes," Mustafi told Der Spiegel. "And I can cope with harsh criticism.
"But the criticism escalated, became irrational. I became a target. And we reached a point where people held me responsible for defeats in games I didn't even take part in.
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"I was annoyed (about Petit's criticism). It is one thing when you are criticised by fans or media.
"But it's a totally different thing if an ex-player, who knows how difficult it can be out there on the pitch, says something like that. I expect those players to be more sensitive and realise what they can initiate with such harsh criticism.
"Back in the day, it would have been in the papers for maybe a day and people would have forgotten about it. But it is written on the Internet today and will haunt me for the rest of my career.
"Former players like Petit should really not need to make their mark by talking current players down."
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