Diego Costa somehow managed to avoid receiving his marching orders today, despite tussling with every available Arsenal player on the pitch.
The Chelsea striker is renowned for his bully-boy tactics, but his mad-man aggression reached new levels this afternoon, as he miraculously avoided dismissal on numerous occassions.
Arsenal manager Wenger condemned striker Costa for his actions that led to the dismissal of Gabriel.
"(There is a) big sense of injustice," Wenger told BT Sport 1. "I think Diego Costa is a red card.
"I wouldn't like to be Mike Dean tonight because I cannot understand the situations. Twice he (Costa) should have been sent off.
"Look at the situation well before the cross comes in, he hits him (Laurent Koscielny) in the face on purpose.
"He makes a fuss of it. In every game there is aggravation but he gets away with it because of the weakness of the referee.
"We are guilty because we gave in on that and responded to it. We knew before the game that he was only looking for that and when he touches him he goes down like he has been killed."
In response, Chelsea boss Mourinho said: "The game is about all different aspects. The technical, emotional, physical and with a combination of these factors normally the best team wins. We were the best team. We were dominant, we were in control.
"I played my first derby as manager in September 2000 and I remember my words to my players. To win the derby - emotional control. I always repeat the same words before derbies.
"For me it was a fantastic performance (from Costa). He played the game like the game has to be played. He's fast, he's aggressive and he's good to recover the ball and offers us different qualities."
Here is some evidence that Costa should have walked:
Diego Costa is certainly a vessel for Jose Mourinho out on the pitch. The combative Chelsea boss loves to get involved in controversial incidents off the field and his chief striker does an excellent job of maintaining the status quo between the lines.