Borussia Dortmund know only too well of Erling Haaland's ability to destroy defences in the Champions League, but the German giants may die by the sword they previously lived by when they visit Manchester City on Wednesday.Haaland blossomed into one of the world's most feared strikers during two-and-a-half years in Germany, scoring 86 goals in 89 games for Dortmund.Eight games into his City career, the giant Norway striker with a devastating turn of speed has already scored 12 times for the English champions."His numbers in all his career, not just here but when he was in previous teams, is quite similar," said City boss Pep Guardiola after Haaland struck twice in a 4-0 win at Sevilla to kick off City's latest quest to break their Champions League duck."He has an incredible sense of goal."Haaland's bargain 60 million euro (£51 million, $63 million) buyout clause meant he had his choice of clubs after he had outgrown his surroundings in the Bundesliga.Dortmund may provide the perfect breeding ground for Europe's top talents to develop in the early years of their career, but they cannot compete financially with the continent's wealthiest clubs, nor satisfy the ambitions of the world's best players in the long term.Haaland followed in the footsteps of Jadon Sancho, Christian Pulisic, Ousmane Dembele, Pierre-Emerick Aubameyang, Robert Lewandowski and Mario Goetze as stars of the future to fly the nest after briefly leaving their mark in western Germany.However, losing Haaland may prove the biggest loss of all with the 22-year-old threatening to rewrite records set by Cristiano Ronaldo and Lionel Messi that many believed would remain intact for generations.Haaland's double against Sevilla took his tally in the Champions