Ferguson passed on his best in a text to Speed's assistant Sam Ellis and the Welshman, who has added John Carver to his backroom staff, has been boosted by all the good-luck messages he has received.
"Sir Alex Ferguson always likes to give people a call when they go into the business," said Speed, who has succeeded the unfortunate Kevin Blackwell. "And he's been in touch to wish me luck.
"I've been really busy, as you would expect, but he sent Sam, my assistant, a text to pass on. It was a really nice touch.
"I've had quite a few from people I know in the game because, despite what some might think, it's quite close knit. But they probably won't be quite so supportive if I come up against them in competition!"