"QPR need a point and they're fighting for survival," said Ferguson.
"The whole future of the club could be resting on the game and I only wish Sparky was playing.
"But Mark knows his job all right. He was sacked by City in a very unethical way and he'll remember that."
And that could contribute to a collapse as dramatic as the one suffered by Devon Loch in the 1956 Grand National when he appeared to have the race at his mercy.
"There could be a Devon Loch. You never know," said Ferguson.
"Stranger things have happened in this game of football.
"They're red-hot favourites but we've won the title on three occasions on the last day and we don't mind doing it again."