The 21-year-old Bayern Munich star all but ended his former side's Bundesliga hopes to leave BVB's season hanging in the balance.
Now, BVB is staring at what seemed impossible after an intense summer of rebuilding - an early end to its title challenge and a do-or-die clash in Europe with Napoli.
|FROM OUR LIVE COMMENTARY|
|66'||GOTZE SCORES!! BAYERN ARE AHEAD!! Dortmund's fans fall silent as the man that deserted them in the summer controls a pass from Muller on the right and sends a sumptuous effort with the outside of his right foot into the left corner.|
It seems that everything that could have gone wrong over the last month has gone wrong. First a surprise loss in the return fixture against the Gunners, who scored with their first credible chance of the game after BVB had squandered a number of opportunities. The result left Jurgen Klopp's side on the brink in Europe.
Then, the injuries came. Days later, Dortmund lost Neven Subotic in a 2-1 defeat to Wolfsburg and the international break saw Marcel Schmelzer and Mats Hummels succumb to injuries while on Germany duty.
Even, so BVB would have lived in hope of pulling off a surprise result against Bayern, given its superior record over the Bavarians in recent years and the hint of romance that has surrounded the Westfalenstadion over recent years.
It was not to be. Once again, everything went wrong for Klopp's side. Bayern was oddly sluggish in the opening exchanges of the match, struggling to trouble BVB's cobbled-together defense and gifting its hated rival a plethora of chances.
But the ability to finish abandoned first Robert Lewandowski, then Marco Reus and Henrikh Mkhitaryan.
Then the unthinkable happened. Mario Gotze, the former golden boy of the Ruhr giants, rose from the bench to break Borussia hearts. Within minutes, he silenced a crescendo of boos that greeted his arrival with a fantastic goal, showing the sort of finesse his former teammates and successors were sadly missing.
His arrival changed everything and won Bayern the match. Prior to his entry, the Bavarians were offering precious little and the underdogs looked the likelier. Thanks to him, Bayern was able to add considerable gloss to the result, adding a second and a third in the closing minutes to rub salt into Dortmund's wounds.
And so Bayern marches on. The Bundesliga was supposed to be a two-horse race this year, but Pep Guardiola's side has taken a critical advantage before the end of November, placing itself seven points clear of last season's runner-up.
As for BVB, it must dust itself off and focus on the challenges ahead, most pertinently the visit of Napoli on Tuesday. Lose, and its horror month will have killed off its season.
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