Defender Nico Elvedi netted twice as Moenchengladbach ended their six-year wait to beat Dortmund when their 4-2 home win on Friday lifted the Foals to fifth in the Bundesliga table.
Two goals by Dortmund striker Erling Braut Haaland were bookended by Elvedi netting from set-pieces in the action-packed opening 32 minutes.
Algeria left-back Ramy Bensebaini restored Gladbach’s lead early in the second half before substitute Marcus Thuram headed the hosts’ fourth.
Dortmund are now seventh — out of the European places — after failing to win any of their last three games since their impressive 3-1 win at RB Leipzig in early January.
In the other direction, Gladbach are fifth having taken 13 points from a possible 15 in 2021. They are eight points behind leaders Bayern, who are at bottom side Schalke on Sunday.
Following home wins over league leaders Bayern and second-placed RB Leipzig already this season, Gladbach claimed another big-name Bundesliga scalp.
It was also a significant win for their coach Marco Rose, who the German media are tipping to replace caretaker boss Edin Terzic at Dortmund next season.
“We went 3-2 up at just the right moment and then defended well, so we’re very happy,” said Rose.
After 12 straight defeats to Dortmund, Gladbach earned their first win over the Black-and-Yellows since April 2016. “We’re finally ended the run of defeats,” Rose added.
Dortmund made a lethargic start at Borussia Park and a Gladbach goal after 44 seconds was ruled out by the VAR.
However, the hosts took the lead with 11 minutes gone when Lars Stindl’s curling free-kick was headed home by Elvedi.
Dortmund roared back with two goals inside six minutes, both created by Jadon Sancho for Haaland, who fired home his first from a tight angle on 22 minutes.
After Jude Bellingham won the ball back for Dortmund, great footwork by Sancho then again unpicked Gladbach’s defence for Haaland to blast his side 2-1 ahead on 28 minutes.
However, another Stindl free-kick on 32 minutes could only be parried by Roman Buerki and Elvedi tapped home the rebound from close range to make it 2-2 at the break.
Gladbach regained the lead five minutes into the second-half when Bensebaini swung in a shot which curled outside Buerki’s grasp.
Dortmund conceded their third goal of the night from a set-piece when Thuram headed home a Florian Neuhaus corner 11 minutes from the whistle.
It was the France forward’s first appearance after suspension for a spitting at an opponent last month.