Berlin: Teenager Erling Braut Haaland scored twice off the bench as Borussia Dortmund moved up to third in the Bundesliga with a 5-1 thumping of Cologne.
Having claimed a hat-trick as a substitute on his Dortmund debut last Saturday to inspire a 5-3 win away at Augsburg, Haaland, 19, again showed clinical finishing.
With his team 3-1 up, Haaland came on for his first home appearance with an hour gone and 11 minutes later was on the scoresheet, slamming home the rebound of a saved Julian Brandt shot.
He then showed his speed to beat Cologne goalkeeper Timo Horn, tucking the ball into an empty net on 87 minutes.
The result leaves Dortmund level on 36 points with defending champions Bayern Munich and four behind leaders RB Leipzig.
Goals by Raphael Guerreiro and Marco Reus gave Dortmund a 2-0 half-time lead.
England winger Jadon Sancho grabbed a third after the break and Cologne striker Mark Uth claimed his first goal for the visitors before Haaland's entrance.
The teenager has 33 goals in 24 games this season having netted 28 times for Salzburg before Dortmund snapped him up for 20 million euros ($22 million) last month.
Dortmund were ahead with less than a minute gone at Signal Iduna Park as Sancho threaded a pass through to the unmarked Guerreiro who slotted home a first-time shot.