Dortmund knocks off rival Schalke
Mkhitaryan was involved in all of his side's goals, after the 143rd Ruhr derby was delayed due to flares causing thick yellow smoke in the Dortmund fans' stand.
As referee Knut Kircher led the teams back off the pitch, Dortmund goalkeeper Roman Weidenfeller appealed to the hooded supporters to desist, only to have lit flares thrown in his direction. Dortmund fans were also blamed for rioting before the game.
''They're not pretty pictures, to put it mildly,'' Dortmund coach Juergen Klopp said. ''You feel shame at times like this. I'm often proud of our fans but that was disruptive in the truest sense of the word. We won despite it, not because of it.''
Once play got underway, Dortmund seized the initiative. Mkhitaryan sent Marco Reus through to cross for Pierre-Emerick Aubameyang's opening score in the 14th minute.
Schalke had the chance to equalize after Neven Subotic conceded a penalty against Christian Fuchs in the 30th, but Kevin-Prince Boateng failed to convert against his former club when Weidenfeller saved his spot kick.
Mkhitaryan led a counterattack to set up Nuri Sahin's wonderful 20-meter (yard) strike in the 51st, and the Armenia midfielder led another in the 74th for Jakub Blaszczykowski to seal the result, 12 minutes after the 18-year-old Schalke substitute Max Meyer pulled one back on a rebound.