By ESPNSTAR.com staff
The Frenchman has seen the plot unravel for his side in recent times. They have lost three of their last four games and now lie nine points behind United in the Premier League.
The Gunners were also sub-standard at Old Trafford on Saturday and were trailing for much of the game after Robin van Persie and Patrice Evra put United ahead.
To make matters worse, Wilshere was sent off in the 70th minute for collecting a second booking after catching Evra with his studs in a mistimed challenge.
But despite the seemingly legitimate reasons for the dismissal, Wenger has come out harshly against Dean's handling of the game, saying the referee made it easy for United to get the Arsenal midfielder sent off after his initial booking and he also criticised Evra for exaggerating the intensity of the challenge.
"The red card was very harsh," Wenger told the Guardian.
"I find the referees very naive because when you say to the players, 'Look for the next foul and you'll get a second yellow', that means a signal for everybody of the other team to dive. And of course they do it.
"He [Wilshere] went for the ball and Evra made the maximum of it. To me it looked a regular challenge."
And he dismissed concerns that certain Arsenal fans were disrespectful towards Robin Van Persie in the game. The Dutchman faced his former side for the first time in a Red Devil jersey and refused to celebrate his early goal in the game.
“Our fans were fantastic today [Saturday],” Wenger continued. “They were always behind the team.
“They expressed their disappointment because I’m sure they love Robin and that’s it.
"I don’t think they were disrespectful. I didn’t listen to that. It’s shown more that they were disappointed that he joined Man United.”
The 63-year-old also had to admit that it was one of Arsenal's worst defensive performances in the current season. He is also uncertain if the club will be able to get back into the title race although he noted that they have completed a series of tough away fixtures.
"We were poor today [Saturday] defensively, I think," Wenger said. "There's no obvious reason apart from the fact that we didn't start well and that Man United have quality up front.
"They score goals against anybody and they're better than us, as simple as that.
“At Man City, we played a 1-1. We had a good result and didn’t suffer from [the] comparison. I just think at the moment we are not on full cylinders and we looked much more vulnerable defensively than we were at the start of the season.
“That’s what we have to show [that the team can compete for the title]. At the moment, you cannot say that because we are far away.
"But that’s what the target is until the end of the season."
“We’ve played many away games now in many difficult places. We’ve played at [Manchester] City, at [Manchester] United, at Liverpool [and] at Stoke. So we have had many difficult away games.
"But we are very far behind now.”
Arsenal return to Champions League action with a vist to the Veltins-Arena to take on Schalke on Tuesday.