Real's advantage is not so great that any result in this game will be anything special. And by the way, if you compare it with comebacks in the playoffs when after the first game the underdog team reverses the result, then the comparison will definitely be in favor of two-game confrontations.
And about the unexpected: Atalanta's victory, United's victory... perhaps that's enough
It’s the champions league and more than Real Madrid whom has won the trophy severally, Dortmund wants it more. I’ll like to see them play like they want it and I’ve got reasons to believe they are not going to disappoint me. Real Madrid remains the favorites to win and the only way Dortmund can pose any significant threat is flaying an attacking game with Real Madrid. It’s how Manchester almost got to win them and we saw Real Madrid being defensive in hope for a penalty shootout.
Get to that point and the game is pretty much a 50:50 chance where the best goalkeeper can help save the day and decide the win.