A brace from Thorgan Hazard and further goals from Andre Hahn, Patrick Herrmann and Ibrahima Traore were enough to send Gladbach back into fourth place.
They are now a mere three points behind Hertha - with just four points separating the teams in third and seventh - as the season nears it's end.
Rune rues his mistake
The battle between the two top four teams got underway and it was the hosts, Mönchengladbach, who started the better. Andre Hahn, making his return to first team football after a horrific injury, had the first chance of the game but only managed to fire high and wide.
The chance was quickly forgotten about as Gladbach took the lead in the 14th minute through Thorgan Hazard. Rune Jarstein's dreadful pass out from the back was quickly intercepted by Lars Stindl and the midfielder found Hazard, who slotted in to make it 1-0.
The visitors struggled from start to finish and were close to conceding again with 25 minutes gone but Granit Xhaka's header just missed the frame of the goal. Vedad Ibisevic managed to go close to equalising for Hertha BSC but his shot was saved well by Yann Sommer.
With ten minutes left in the first half, Vladimir Darida went close from outside the box but his shot narrowly missed the top corner.
The first half was controlled by the hosts for the most part and they were rewarded with a goal from a terrible mistake from the Hertha goalkeeper.
From bad to worse
If the first 45 was tough for the visitors, the second half was much worse. Gladbach doubled their lead on the hour mark with a thumping finish from Hahn on his return. He capped off his first game with a wonderful swivel and finish into the top corner to make it 2-0. Moments after the goal, he was replaced by Patrick Herrmann, also making a return to first team football after injury.
Fabian Johnson was inches away from making it 3-0 but a fantastic stop from Jarstein denied the American. Hertha kept trying to create a chance for a late comeback and Salomon Kalou had his header from close range saved by Sommer. Just after entering the last quarter of an hour, it was a 3-0 lead for Mönchengladbach.
Patrick Herrmann's cross was met by Hazard, who had his shot saved by the 'keeper but Herrmann followed up to tap in Gladbach's third and capping off his return, similar to the man he replaced. Hazard grabbed his second of the game with ten minutes left after Mahmoud Dahoud fed the Belgian after winning back possession and the attacker's shot deflected past a helpless Jarstein.
Gladbach hit for five in the 85th minute as substitute Ibrahima Traore completed the rout but slotting under the 'keeper, who perhaps should have done a lot better. Into stoppage time, Herrmann almost grabbed a second but was denied by the crossbar, meaning it ended 5-0.
Andre Schubert's men were excellent from the first whistle and thoroughly deserved their win. The three points boost their top four credentials and the returns of Hahn and Herrmann will prove to be huge. For Hertha BSC, they remain in pole position to finish third but a heavy defeat to top four rivals will play on their minds.