A goal from loanee Hannes Wolf put Borussia Monchengladbach into the top four while ending the unbeaten start of his parent club RB Leipzig.
Die Fohlen thoroughly deserved their first ever win against Leipzig with a strong team performance seeing them through the last twenty minutes.
Leipzig, meanwhile, lacked a cutting edge throughout and seemed to be suffering from a hangover after their thrashing in midweek.
Borussia Monchengladbach - Yann Sommer; Stefan Lainer, Matthias Gunter, Nico Elvedi (Sub, 45'), Ramy Bensebaini; Jonas Hoffman, Florian Neuhaus (YC,56',Sub,73'); Patrick Herrmann (Sub,80'), Breel Embolo (Sub,73'), Hannes Wolf (G,59'); Alassane Plea (Sub,80')
Substitutes - Oscar Wendt (45',YC,52'), Marcus Thuram (73'), Christopher Kramer (73'), Lars Stindl (80'), Valentino Lazaro (80')
Leipzig - Peter Gulasci; Benjamin Henrichs, Dayot Upamecano, Willi Orban, Angelino; Marcel Sabitzer (YC,70'), Kevin Kampl (YC,61',Sub,66'), Dani Olmo (Sub,66'), Lazar Samardzic (Sub,70'); Youssef Poulsen (Sub,66'), Alexander Sorloth
Substitutes - Amadou Haidara (66'), Emil Forsberg (66'), Hwang Hee-Chan (66',YC,69'), Christopher Nkunku (70')
Story of the match
The home side started on top, controlling the tempo for the opening 20 minutes. However, there was a sloppiness at the back which allowed Yussuf Poulsen to have a few half chances.
Other than a disallowed Alassane Plea goal just before half time, there was very little goal mouth action in the first half.
Plea again was in the heart of the action at the start of the second half, missing a number of guilt edged opportunities to give the hosts the lead.
However, the most ironic of scorers did eventually hand Die Fohlen the lead with Hannes Wolf, on loan from Leipzig, tucking a neat finish into the bottom corner from just outside the six yard box.
The goal sprung Leipzig to life, with substitutes Emil Forsberg and Amadou Haidara both forcing Yann Sommer into important saves after coming on.
However, they were unable to find an equaliser and Monchengladbach held onto a deserved three points.
In the ninth attempt, Monchengladbach have finally beaten Leipzig. A goal from Hannes Wolf sealed the deal but it was performances from the likes of Ramy Bensebaini and Jonas Hofmann that caught the eye. Both playing out of position, Bensebaini was exquisite at centre back in the second half while Hofmann put in a man of the match performance in centre midfield.
Julian Nagelsmann will be extremely disappointed at his sides performance and the end of their unbeaten start. Neither Alexander Sorloth nor Yussuf Poulsen looked like scoring, although the big Dane did offer more from an aerial point of view. However, youngster Lazar Samardzic did look bright in patches and will certainly see more game time in the future.
Man of the match - Jonas Hofmann
Playing slightly deeper than usual, Jonas Hofmann typified everything that was good about Monchengladbach. Rarely giving the ball away while providing cover for the centre backs, Marco Rose may have discovered a potential ploy for the future.