The Brazilian lifted his game under Ole Gunnar Solskjaer, making 48 appearances across all competitions last season.
Watford beat United at Vicarage Road
"Whenever you play against Fred - we certainly did it - you let him get it because he has to take three or four touches," he told talkSPORT.
"He doesn't know how to do one or two touches.
"Anyone that watches his game, he gets it facing the wrong way, turns, turns, chops, chops and he'll give you the ball three or four times a game.
"It's the truth. If you're anyone who studies football you'll know that, when teams are setting and they're waiting, you go and that one person is the trigger.
"You're waiting for it to go and then you bounce off him."