Erling Haaland's stunning start to life at Borussia Dortmund continued on Friday as he scored twice after coming off the bench in a 5-1 rout of Cologne.

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 sit four points behind RB Leipzig, who lead the way in the German top flight.