He takes his new side to Old Trafford on Saturday believing United have now lost the fear factor they once had.
Hughes, who played more than 400 games for the Red Devils, said: "They can't afford any more slip-ups. Maybe they are a little bit vulnerable.
"I don't think there's that aura around the club at the moment and maybe it's a good time to meet them.
"There are only a certain amount of games you can lose. Five or six keeps you in the title race. Lose any more and you make it very difficult, nigh on impossible."
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