Blind, the father of former United utility man Daley Blind, knows a thing or two about football, having enjoyed an illustrious playing career with Ajax and Holland, and it is fair to say he has not been impressed with what he has seen from Mourinho's side in recent weeks.
Speaking to the 'Daily Mirror', Blind hit out at the way Mourinho sets United up, as well as questioning his recruitment in an all-encompassing rant.
"Jose can't even get the right formation any more," Blind raged.
"He has not bought the right players and the football is not based on a playing style with clarity for the players.
"For example, he is always changing his line of defenders. One match he has five at the back, then four at the back and, when I look at some matches, he is actually playing with six players in a straight line at the back when they have the ball."
Despite being one of the most expensive players in world football, Paul Pogba has slipped out of the United side in recent months, but Blind believes he knows what must be done to get the best out of the Frenchman.
"One thing Jose has to do with Pogba is instruct him to play simple," he explained.
"He is the kind of player who wants to come up with complicated solutions or difficult options. And, in midfield, he wants to have 100,000 touches of the ball.
"He wants to shake off opponents by showing them his strength, a double shoulder push or whatever before he turns with the ball.
"But, in the Premier League, all of his opponents are equally strong, physically. He just can't do it. So make him pass the ball direct and simply."