The 63-year-old has come under intense pressure over the past couple of seasons from the club's supporters as the Gunners have struggled to challenge for honours whilst selling their top players such as Cesc Fabregas and Robin van Persie.
Dein, however, says he finds chants such as 'you don't know what your doing' aimed at Wenger at the Emirates "very hurtful".
“People have got short memories. They seem to forget what Arsene has achieved for the club," he told The Sun.
“Arsenal is respected around the world and much of that is because of Arsene with the results and the players he has brought in and developed.
“People underestimate him. He has transformed the club. He has done a phenomenal job.
“I always used to call him the miracle-worker. He waved his magic wand and he delivered.
“But it’s getting tougher because the competition is getting stronger.”