The former Hearts and Rangers midfielder and his family have three season tickets in the Stretford End having grown up supporting the Red Devils.
Shrewsbury host United in Monday’s FA Cup fifth-round clash, the first time the teams have met in a competitive game.
Victory would be a hammer blow to Louis van Gaal following United’s 2-1 Europa League defeat to FC Midtjylland on Thursday and Black feels the players are to blame.
“Wayne Rooney has come out and said blame the players which is totally right and I totally agree,” said the one-time Scotland international.
“They are getting paid X amount of money to perform to the level they should be at that size of club and they have not done it.
“They have been poor but people write them off and you can never write them off.
“They have been unfortunate with the way they play.
“People talk about the manager and being under pressure but he is the manager at the biggest club in the world for a reason and he can handle that.
“People will always criticise the manager but he can only pick the best XI he thinks and it is always the manager who gets the sack.”
Defeat at Greenhous Meadow would be a nadir in United’s wretched season and Black knows the pressure could toll on Van Gaal should Micky Mellon’s men shock them.
“It would put massive pressure on him if we can go and achieve a result or draw or win,” Black said. “To be brutally honest I can’t tell the board how to act if we beat them.
“It is Man United and you never know how they are going to turn up. Beating them would be a dream, I can visualise it.”
Black won the Scottish Cup with Hearts in 2012 when he was man of the match in the 5-1 final win over Hibs.