The Bundesliga side are used to playing second fiddle to Bayern Munich in German football and, like in previous years, lost a number of key players last summer, but have continued to defy the odds this season, with their comeback draw at the Santiago Bernabeu proving that they can withstand even the most intimidating arena. READ ALSO: Real Madrid 2-2 Dortmund: Zidane ‘angry’ over stalemate
There is no better club for an unknown player to build towards prominence than Borussia Dortmund. The Signal Iduna Park side have over the past few years, with a small budget, overachieved and in the course of that directly ignited the careers of countless hitherto unknown players.
Very few of the stars who have turned out for Die Borussen commanded a reputation before joining the club. Lewandowski, Lukasz Pizczek, Mario Gotze, Matts Hummels, Nuri Sahin, Kuba Blaczykowski, Shinji Kagawa and many others were all made by the club. READ ALSO: Why Iwobi's Arsenal can reach the UEFA CL quarters
For a club with high ambitions, Dortmund have suffered greatly over the years from the loss of key players to other teams, most hurtfully Die Klassiker rivals Bayern Munich. Last summer alone, key men Henrikh Mikhitaryan, Ilkay Gundogan and Matts Hummels and all left for greener pastures, the latter to Bayern. Yet the club has managed to stay competitive even against the best.
They remain true to their commitment of breeding tadpoles into fearless sharks. Julian Weigl, Christian Pulisic, Raphael Guerreiro, Emre Mor and Ousmane Dembele are just some of the precocious talents that the Yellows are currently molding into future world stars.
Most of these players are already proving their mettle alongside golden campaigners like Marcel Schmelzer, Pierre Aubameyang, Marco Reus, Mario Gotze and Andre Schurlle.
A key component of the BVB system remains the no fear factor. BVB always set out to play the opposition, no matter whom, as some say, fire for fire. They have already got one over Bayern in the Bundesliga this season.
One continental giant that can attest to BVB's international prowess are Real Madrid. Just four seasons ago, the Germans ensured that Jose Mourinho's stay as the Blancos manager ended in Champions League misery with that Robert Lewandowski-inspired 4-1 pummeling in the semi-final of 2013.
Madrid have gone on to win the competition in two of the three years after that, but there is always that niggling craving of revenge when you have been left so scarred.
The Spaniards must have hoped to put the nightmare behind them when the draws were rolled out and they found themselves in the same group as their nemesis this season. The first chance of revenge was missed when the two sides played out a 2-2 draw in October in Germany. READ ALSO: Zorya 0-2 Man U: Mkhitaryan nets solo goal, Mata storms off
They came into the last match of the group stages on Wednesday with Madrid two points behind and needing a win to upstage Dortmund at the top. That was not to be, however as Karim Benzema's two-goal lead was cancelled out by goals from the majestic pair of Pierre-Emerick Aubameyang and Marco Reus.
Any thoughts of a Madrid revenge were evaporated in a quick-fire second half siege. Last night's result sent a chill of déjà vu down the Madrid spine while BVB went home top of the group ahead of the defending champions, ready to dare anyone, anywhere.
Dortmund boast a young and dynamic team, a striker as unstoppable as a typhoon, as well as a manager who has been rated as tactically better than Jurgen Klopp an Jose Mourinho by a man who has played for all three.
Their football is captivating and incisive. They have now registered 21 goals in the six-match group stage - a feat that surpasses what anyone else can boast of. What is to be feared most, however, is not their abundance of goals, but their abundance of heart, their bravery; their undying winning spirit.
Thomas Tuchel's men, just like Jurgen Klopp's side before him, are a fearless unit, an underdog that can bite anyone, and, just maybe, go all the way. They are the unfancied campaigners that the big guns must be wary of as the competition progresses.