Wednesday's UEFA Champions League last-16 first leg tie pits two teams who have won the competition 12 times between them.
And Ferguson echoed the view of counterpart Jose Mourinho that this match was one "the world has been waiting for".
"Jose summed it up perfectly," Ferguson said.
"United and Madrid have that romance about them and that honour and worldwide appeal so it probably is the biggest game you can get in the European Cup.
"I think as soon as the draw was made, there was that anticipation about the tie.
"It's a fantastic challenge for myself and it should be a fantastic match between two teams and clubs who embrace the best parts of football, with great reputations.
"The acid test is this game, I have no doubts about that.
"It is unfortunate that we are meeting as early as this. I wish it had been at Wembley (in the final in May)."
While United have opened up a 12-point gap over rivals Manchester City at the top of the Premier League, Real have endured a turbulent domestic season and languish 16 points behind foes Barcelona.
Claiming the pressure would be on for Mourinho to deliver in this competition, the Scot added: "I think Jose has set his targets firmly on the European Cup, no doubt about that.
"It can be hard for us but there's a bit of pressure for them, too. At this moment in time, we're involved in three (competitions)."
You can only watch the best UEFA Champions League coverage here on Sky Sports. Watch Real Madrid v Manchester United exclusively live on Sky Sports 2HD and Sky Go from 6:00pm on Wednesday 13th February. Click here for more details and watch goals from United's route to the last 16.