Vila are at United tonight.
"You'd love to know how he's done it," he said.
"What he's done is nothing short of remarkable. I know him pretty well. I used to go and watch Manchester United training when I was out of work.
"I don't think there's a better manager. I don't think that'll we'll see another manager stay at one club for 27 years. Who's going to do that?
"He's surpassed anything anyone could do. He's won virtually everything, European Cups, league titles. He's a top, top manager."