The 19-year-old netted a hat-trick on debut against Augsburg after being introduced in the 56th minute, having joined from Salzburg this month.
And the Norway international made a similarly emphatic impression after coming on with 25 minutes to go this time around, making it five goals in his first hour in a Dortmund shirt.
Lucien Favre's team were already 3-1 up prior to Haaland's cameo courtesy of goals from Raphael Guerreiro, Marco Reus and Jadon Sancho, with Mark Uth responding.
Haaland first pounced on a rebound to slam in his side's fourth and then deftly tucked home from a tight angle after racing onto Mahmoud Dahoud's pass and leaving goalkeeper Timo Horn stranded.
Dortmund now sits four points RB Leipzig, which leads the way in the German top flight.