Man Utd boss Ferguson: It doesn't get bigger than tonight
Real are at United for the second-leg of their Champions League tie with scores locked at 1-1.
"Real have had two fantastic performances against Barcelona," said Ferguson. "I was there for the first one when they were superb.
"They have found form at the right time for a game of this nature.
"Our form has been consistent for quite a while, which we need for tomorrow night's game also.
"As a European night I don't think you get any bigger than this one.
"It is two great clubs with great histories.
"It is set up to be a marvellous game. I don't think it will be a disappointment."