Leipzig came from behind to score three goals in the second half against Gladbach.
Gladbach established a shock 2-0 lead inside twenty minutes, with Jonas Hoffman scoring from the spot followed by Marcus Thuram off his shoulders.
Leipzig showed their intentions from the start of the second half, with Nkunku and Poulsen finding the scoresheet in the space of no time to get back on level terms.
Substitute Emil Forsberg forced a top-class save from a freekick, which could have ended the game by then.
When everyone thought the tie was over and the game would end up in a draw, Leipzig stunned everyone with a late win through Sorloth’s header.
Julian Nagelsmann’s side is now only three points behind Bayern Munich in the Bundesliga table.
Gladbach appeared to haven’t recovered from their defeat to Manchester City in the Champions League earlier this week and they are winless in their last four league games.
Leipzig boss Nagelsmann offered his thoughts on the victory:
“I was incredibly pleased because it was a totally-deserved victory. We did really well across the whole game, with the exception of the two goals.
We really wanted the win and believed in it until the very end!”
Leipzig will take on Wolfsburg in DFB Pokal Quarter final next week before facing Freiburg and most importantly Liverpool in the Champions League.