Many of the world's media have said that Irmatov's call was a blunder because Steven Pienaar was standing on the line behind Itumeleng Khune, however the ref's decision has been justified with a comprehensive explanation of the rule.
According to a specialist in the world of football referees and the interpretation of the laws governing the game the referee was right to disallow Vela's goal.
"When showing replays, commentators pointed out and graphics demonstrated that there was a South Africa defender (Pienaar,) positioned on the back post -whom they claimed kept Vela onside," the specialist explains.
"It's true that Pienaar was there, and just behind Vela, where he stood by the opposite post. But the crux of matter was the position of Khune, not Pienaar.
"Khune had run off his line to try and intercept the corner kick, leaving Pienaar as the last defender in front of the goal.
"Now comes the crucial point. The offside rule reads that a player is offside if he is ‘nearer to his opponents' goal line than both the ball and the second-last opponent (the last opponent typically being the goalkeeper).
"Usually when an attacking player runs past the ‘last defender,' the goalkeeper remains in the net - meaning the ‘last' defender is really the second-to-last defender. In the case of Friday's game, Khune was not there behind the defence.
"The second Vela passed Khune in the middle of the box, he was offside, regardless of Pienaar's position at the post.
"It was an intelligent call from the referee and his assistant in a complicated demonstration of a complicated rule," he adds.