The first Bundesliga derby between Union Berlin and Hertha Berlin ended in victory for the home side thanks to a late penalty conceded by former Celtic defender Dedryck Boyata.
The Belgian defender was penalised for bringing down Christian Gentner, with VAR confirming the referee's decision.
Union substitute Sebastian Polter, who had only come on the park ten minutes earlier, converted the penalty to seal victory for the first club from east Berlin to reach Germany's top flight.
Ten minutes of stoppage time was added on at the end of the 90 minutes after fans threw flares at the start of the second half, leading to the temporary stoppage of the game.
Players were taken off the pitch but later re-emerged to continue the match.
The fixture, played at Union's atmospheric and iconic Stadion An der Alten Försterei, was the first Bundesliga meeting between clubs from east and west Berlin.