It's the matchup that Manchester United fans both feared and salivated at the prospect of only a few hours ago.
Jose Mourinho's too—let's not forget his illustrious history at the Theatre of Dreams. It seems like only yesterday when, as the then-Porto boss, he ran down the tunnel giddy having seen his team trump the European giants on their own turf.
Many will write off the Red Devils' chances—speak up the undeniable talents of CR7, Iker Casillas, Xabi Alonso, etc. But the reigning La Liga champions have not looked anywhere near the dominant force they were last season.
Sir Alex Ferguson's men, on the other hand, may not have played anywhere near their best this term, but have stepped up for the most important games on the fixture list.
Though it will certainly prove a daunting task, a full-strength United are certainly capable of beating the Spanish giants.
Here's a look at Real's strengths and weaknesses, and the keys to what will prove the most eagerly anticipated game of the season.