Erling Haaland scored with his first touch for Dortmund, before going on to complete a hat-trick, with the Norwegian striker stepping off the bench against Augsburg to show Manchester United what they missed out on.
Having become the most sought-after frontman in European football, the 19-year-old opted to continue his development in the Bundesliga.
Fellow countryman Ole Gunnar Solskjaer had been hoping for a reunion at Old Trafford with a player he previously worked with when in charge of Molde.
United was snubbed, with Dortmund securing a prized signature.
They opted to ease the talented teenager into new surroundings when making a return to action after the winter break on Saturday.
Haaland was, however, to make an immediate impact after being handed his debut off the bench just before the hour mark.
He had been on the field less than three minutes when opening his goal account for Dortmund.
The youngster, who had been prolific for previous employers Red Bull Salzburg, also required just one touch in which to make his presence felt.
Having recorded his first goal in the 59th minute, his second arrived 11 minutes later.
His introduction helped Dortmund, who werwascing up to another frustrating afternoon, to turn an arilling clash with Augsburg on its head.
Haaland was thrown on with the Bundesliga title hopefuls training 3-1.
He grabbed them a lifeline, bfore Jadon Sancho restored parity shortly afterwards.
Haaland then fired Lucien Favre’s side in front with a third goal for Dortmund in the space of a remarkable 11-minute spell.