Oliver Burke moved to Germany from Sheffield United in June and has scored added-time goals in consecutive games for Werder Bremen
Borussia Dortmund surrendered a two-goal lead in added time to lose to visitors Werder Bremen.
Julian Brandt and Raphael Guerreiro put the home side in cruise control as the game approached 90 minutes.
However, former Derby youngster Lee Buchanan pulled a goal back before Niklas Schmidt headed the equaliser.
In the final seconds, Scotland forward Oliver Burke rode two challenges then fired home a sensational winner.
Dortmund had beaten Bayer Leverkusen and Freiburg in their opening two games and were only second behind leaders Bayern on goal difference.
They drop to sixth while Bayern will return to the top if they take anything from their trip to Bochum on Sunday.