'Gladbach took the lead at home on the stroke of half-time through Mike Hanke, but the visitors hit back soon after the break, with Tolgay Arslan smashing the ball past Marc-Andre ter Stegen from close range.
Augsburg thrashed Hertha Berlin 3-0 in the Bundesliga on Saturday, in Otto Rehhagel's first game in charge of the capital club.
The German coaching legend, who has won the Bundesliga three times, joined Hertha this week to try and save the club from relegation.
The Berlin-based club went into Saturday's game just above the relegation zone, but Rehhagel got a good look at how tough his job will be as Augsburg destroyed the visitors with three goals in the second half.
Torsten Oehrl was the match-winner for Augsburg with two goals in two minutes.
Marcel Ndjeng finished the scoring with a goal in injury time, to hand Hertha their 11th defeat of the season.
In Mainz, the home side thumped relegation-threatened Kaiserslautern 4-0.
Former Borussia Dortmund striker Mohamed Zidan got Mainz going with a goal after just two minutes, while Adam Szalai, Nicolai Muller and Maxim Choupo-Moting also got on the score-sheet for the home side.
Freiburg, the only team below Kaiserslautern, also suffered a big defeat, going down 4-1 in Stuttgart, with Martin Harnik scoring twice for the home side.
Bayer Leverkusen strengthened their chances of playing European football next season with a 2-0 triumph over Cologne.
Midfielder Lars Bender was the hero for Leverkusen with a goal in each half.
The 22-year-old tapped in after a corner in the 16th minute and then completed the win with a calm finish five minutes after half-time.
Elsewhere on Saturday, Hoffenheim defeated Wolfsburg 2-1 away, with Sven Schipplock's late goal the difference between the two sides.
Borussia Dortmund maintained their four-point lead atop Bundesliga with a win over Hannover on Sunday.
Juergen Klopp's Dortmund side recorded a 3-1 win at home over Hannover thanks to Robert Lewandowski's brace.
The Polish striker gave the champions a 27th-minute lead when he struck at Signal Iduna Park against a Hannover side chasing a European spot this season.
Lewandowski made it 2-0 for his team nine minutes after the break, but Hannover responded through forward Didier Ya Konan on the hour-mark.
Any hopes of a late Hannover comeback were ended in the second minute of added time when Croatian forward Ivan Perisic came off the bench to make it 3-1.
Bayern Munich managing a 2-0 win over title rivals Schalke at Allianz Arena.
Franck Ribery scored either side of half-time as Jupp Heynckes' team kept the pressure on Dortmund.
Werder Bremen lost 1-0 at home against Neurnberg. Alexander Esswein
