The 29-year-old is in the process of finalising a move, with a medical undertaken on Sunday , and Irwin believes the South American will prove to be a shrewd addition for the Red Devils.
The former United defender told Reuters : “When a player of that ability comes along, I think you have got to be in the market for him.
“He’s a player who knows the Premier League, his goal record ... he’s an experienced international. He’s quick, he’s strong.
“It would be great if he comes to Manchester United because he would not just add to our squad but our team. He’s a really good player and I think he will be a good addition, really good.”
Sanchez is being signed to help force United back into the Premier League title picture, with City still heavily fancied to run away with the crown this season.
He will be drafted into a side Jose Mourinho has carefully pieced together, with the Portuguese another of those to have been acquired on the back of a proven track record.