Having said all that, United do boast a Champions League record of 11 straight home wins.
Ferguson said: "It is a marvellous record that surpasses any other team.
"But that will not change the aspect of this game.
"It will be very balanced, very open and fascinating tactically at times."
Fergie has called upon a capacity crowd to turn Old Trafford into a cauldron - just as the Nou Camp was.
A special appeal has gone out to "wear your colours" with flags and banners encouraged to be brought on the night.
Ferguson said: "We must match their support, hopefully even better it.
"So show your colours, wave your scarves, hoist your flags high and make your presence felt.
"With your help we can do it. The players are ready to do their bit too."
