So far it is honours even after each won a leg of their Carling Cup semi-final last month, although United ultimately prevailed 4-3 on aggregate.
It is 16 years since Ferguson found himself up against Nigel's father Brian, with the Scot edging his 16 meetings with the Nottingham Forest boss by seven wins to six, with three drawn.
Since the most significant of those victories, a 1-0 FA Cup triumph at the City Ground in January 1990 which many claim spared Ferguson from the axe, he has since won everything in the game.
But is he better than Clough, who achieved something Ferguson has yet to deliver in back-to-back European Cups, and with a small, provincial club?
"It's difficult for me to say with my family connections," Clough said.
And then, pointing to the ceiling in the trophy room at Pride Park, he added with a smile: "That light might come down and hit me."
Speaking about Ferguson, Clough added: "He is certainly up there.
"The length of time he has been doing it is the most staggering thing in modern football.
"It's easier in some ways being at Manchester United, the biggest club in the world.
"But in other ways it's harder because you have to maintain that standard.
"His teams have evolved. Every few years you have a few youngsters come through, mixed in with good signings.
"He's never been afraid to spend money, and when you're at the biggest club in the world, why not?"
Money was something Clough Snr had little of during his 18 years at Forest, certainly in comparison to Ferguson.
"You can't really compare in that way," Clough added. "I think you can compare with Sir Alex during his time at Aberdeen, winning a European trophy at a small, unfashionable club.
"That probably stands comparison a bit better."
It is remarkable to think Clough and assistant Gary Crosby played in the Forest side which lost to United on that night 19 years ago when Mark Robins scored the only goal of the game.
But for a different bounce of the ball, they could have played their part in bringing to an end a managerial legacy before it had barely started.
"Of course, we were unaware of the significance of it at the time," said Clough.
"But as time goes on and history kicks in, then it was a pivotal moment.
"You are never quite sure. Was he going to get the sack? It makes for a good story though doesn't it?"
Now it is up to his Derby side to try and inflict a second defeat in a matter of days upon Sir Alex's current team.
Clough believes it is possible, adding: "In a one-off cup tie, lightning can strike twice.
"That may be counter-balanced by their determination to put things right from the last time because they were below par that evening.
"I'm sure they won't want that to happen again, so we're going to have to produce something close to that, if not better in order to get a result."