Haaland became one of the most feared forwards in the world for two and a half years in Germany, scoring 86 goals in 89 appearances for Dortmund.
Eight games into his career at City, the Norwegian striker giant with devastating speed has now scored 12 times for the English champions.
"His numbers throughout his career, not just here but at previous clubs, are quite similar," said City manager Pep Guardiola after Haaland scored twice in a 4-0 win over Sevilla to kick off the game. to City's latest quest to break their Champions League Duck.
"He has an incredible sense of purpose."
Haaland's €60m (£51m, $63m) release clause meant he had his choice of clubs after having outgrown his surroundings in the Bundesliga.