The last time Borussia Dormtund and Real Madrid played, it was the Germans who defeated the favored Spanish giants and won three points to move atop Group D.
Playing in front of one of the loudest, most relentless crowds in Europe, Jurgen Klopp's men took control of the Group of Death by outplaying Cristiano Ronaldo & Co. in convincing fashion.
The champions of Germany did not win the possession battle, but put twice as many shots on goal and troubled Madrid's back line all night.
The scariest part is that Die Borussen were never even really at their best.
To this point, Borussia Dortmund have been the best team in the Champions League and a sweep of one of the tournament favorites would legitimize their status as title contenders.
More of the same?
A return to fitness in key areas for the Spanish champions will help resolve struggles from two weeks ago, but there is no guarantee that the key battles will be decided any differently.
Raphael Varane started his first Champions League match, but it was Pepe who looked like a teenager by being constantly caught out of position and losing the ball repeatedly.
and Marco Reus made Jose Mourinho's choice to play Michael Essien at left back look like a rookie mistake, but damage from the poor decision was rather limited in the end.
Alvaro Arbeloa will be back for the second leg, which will bring some comfort to Madridistas, but if he starts, he will likely be used on the left flank—a position he is comfortable in, but which is not his natural side.
Reus will have another chance to expose Los Merengues' left flank.
The key change
While having a true fullback on both sides will greatly help Madrid, the key battle will be played a bit more centrally.
Over the last couple of seasons, Sami Khedira has formed one of Europe's best midfield pairings with Xabi Alonso.
His importance to the first move of Real Madrid's counterattack and his strength as a shield for the defense is great.
Xabi Alonso is now fit and rested, but his German teammate is not and will miss the key match.
When Khedira went down again in the first leg of this fixture, Luka Modric stepped up and did a decent job in his stead, but the Croatian is just not the same type of player.
Modric has been solid in his first season under Mourinho, but his biggest impact has been as a deeper playmaker.
With Mesut Ozil having his worst season in Spain so far, it is fair to argue that Modric has really been the better player overall.
The decisive battle
While Modric has generally been better or at least on par with Ozil, he does not have the same defensive strength as Khedira and it is that part of the German's game that will be most missed against Dortmund.
With Reus, Mario Goetze and
Die Schwarzgelben have won only two away matches in all competitions this season and have not won an away match in Europe since 2003.
This goes without mentioning the ever-present X-factor, Cristiano Ronaldo, who has scored 14 goals in his last 10 Champions League matches.
Dortmund have been the best team in the tournament so far, but Real Madrid are in good form, and the advantage of playing in front of their home fans cannot be over-valued.
The Spaniards will once again be favored to win, with a draw being a great result for Jurgen Klopp.
Of course, if Dormtund have proven anything this season, it is that despite being the best team in Germany in the past two years, they continue to surprise people with just how great a team they are.
Winning this match would put the Germans at the very top of any contenders list right now.