With both sides sitting on their worst respective points tallies after 25 league matches since 2014/15, Dortmund at least had their midweek UEFA Champions League success to provide a confidence boost, and Serhou Guirassy tested Peter Gulacsi with a low strike early on.
But that only served to ignite Leipzig, who soon struck the bar through Lois Openda, before taking the lead on 18 minutes.
David Raum’s powerful strike was parried into the path of Benjamin Sesko, who was fortunate to accidentally flick the ball back for Xavi Simons to power in from the centre of the area.
The hosts showed no signs of slowing down after notching that opener, and Marcel Sabitzer sustained an injury when preventing Christoph Baumgartner’s shot, before Ridle Baku curled against the crossbar.
It looked as though Dortmund would be relieved to only go into half-time one goal down, but they could easily have equalised when Karim Adeyemi cut inside and had a low shot saved by Gulacsi during first-half stoppage time.
But that hard work - and any of Kovac’s words during the interval - proved in vain, as Leipzig doubled the advantage just a couple of minutes after the restart.
Xavi lifted his corner over the crowd to Openda, who sent a beautiful side-footed volley back across goal and into the far corner.
That finally woke the visitors from their slumber, and Maximilian Beier embodied their determination to try and rescue a lost cause, striking the woodwork twice in quick succession, before Adeyemi did the same as his thunderous strike was tipped onto the bar by Gulacsi.
Dortmund’s response after being pegged back for a second time was admirable, but a multitude of chances went begging thanks to some wayward finishing.
Ultimately, the visitors were unable to even get one back despite racking up over 2 xG in the second half, and they therefore slumped to defeat for a fourth time in six league matches under Kovac.
Although the victory is not enough to see them ascend into the top four, Leipzig’s second win from 10 league matches in 2025 at least takes them provisionally level on points with Eintracht Frankfurt.
Flashscore Man of the Match: Xavi Simons (RB Leipzig)