Borussia Dortmund completed the double over their namesakes from Monchengladbach with a 3-1 win at the Borussia Park Stadion on Saturday evening.
Marco Reus put Dortmund in front with a game against his former club and Henrikh Mkhitaryan made it two just after the interval.
Raffael pulled a goal back to make things interesting, but Ilkay Gundogan restored Dortmund's two-goal lead which they did not relinquish as they returned to within eight points of league leaders Bayern Munich -- and perhaps more importantly, increased their advantage over third-placed Hertha Berlin to eight.
With some fine interplay, Gladbach were finding it easy to slice through the Dortmund defence early on, although the final ball was ultimately lacking.
Ibrahima Traore was twice guilty -- first drifting offside, and then sending his pass too far wide for Raffael to get in a shot -- but the hosts were persistent.
A fortunate deflection put Pierre-Emerick Aubameyang through for his first chance in the 26th minute, but Yann Sommer was quick to react in the Gladbach goal and he was able to thwart the league's top-scorer.
Not even a full-stretch Sommer could get to Gundogan's well-struck 25-yard effort, but fortunately for the Swiss goalkeeper the ball struck the top of his crossbar.
Aubameyang scuffed a free shot wide as the chances started to multiply for the visitors, and the pressure paid off when Reus, minutes after sending an intricate backheeled effort wide, latched onto Gundogan's pass and picked his spot in the far corner of Sommer's goal.
Gladbach came out for the second half with more intent, Traore finding room for a shot which Burki saved before Lars Stindl sliced the rebound wide.
It was better from the hosts, but on the break Dortmund made it two within a flash.
Gundogan sent Reus down the right and his low pass picked out the unmarked Mkhitaryan, who did not even need to alter his stride as he tucked the ball past Sommer.
It was not game over just yet, though. Gladbach pulled a goal back through Raffael, who rolled the ball past Joo-Ho Park with his studs before striking it left-footed into the bottom right-hand corner of Roman Burki's goal.
There was a buzz around the Borussia Park and Gladbach fed off it. So too did Dortmund, however.
They continued to play Gladbach at their own game, bursting forward on the counter-attack whenever they stymied an attack, and the pace of Aubameyang took him clear only for an uncharacteristic miss to let the hosts off the hook.
It was not long before the next Dortmund break, and the next Dortmund goal.
Mkhitaryan was sent deep by Sokratis Papastathopoulos and the Armenian's cross was met by Gundogan, whose side-foot volley level with the near post crept into the far corner.
Jonas Hofmann wasted a good chance to mark his Gladbach debut with a goal against his former club, but the way he half-heartedly struck his effort wide summed up the home team's dissipating belief that they could find a way back into the game. Ultimately, they could not.