Albion, under Clough,famously held Ferguson's United to a goalless draw in the FA Cup third-round back in 2006, before losing in a replay.
The Championship club are facing another famous fixture on Wednesday when they face City in the Carabao Cup semi-final.
"I think this one [is more difficult] over two legs," Clough said. "I think the pitch is going to be a bit better this time around, if anybody remembers the pitch against Manchester United!
"But we're facing similar sorts of tasks. When [Wayne] Rooney and [Cristiano] Ronaldo came on after 59 minutes here for Manchester United, it's a similar sort of prospect with the likes of the quality that Manchester City have.
"But away from home, it's a different thing. When they are on their own patch, as you saw against Liverpool, they are as good and as confident as anything.
"That's when they've come off a relatively poor period for them, they have lost a couple of matches recently and then they can still play like they did against Liverpool and keep the title race open.
"That says an awful lot about them."