Frankfurt shut out for 4th straight
Luuk de Jong's goal midway through the first half was enough for Lucien Favre's side to take all three points from the Waldstadion with a performance reminiscent of their best from last season.
The Foals relied on a strong and efficient counter-attacking style to snatch all three points and to move into the frame for a second straight season in the Europa League, while Frankfurt will drop out of the top four this weekend if Freiburg win in Nurnberg.
Gladbach goalkeeper Marc-Andre ter Stegen got an early touch of the ball when he collected Takashi Inui's weak shot in the first minute.
He did not have much more work to do as his defence kept Frankfurt at a safe distance from his goal while the visitors waited patiently for their chances on the counter attack.
When opportunity knocked, it was usually Amin Younes seeking out the killer pass, finding one in the 19th minute to send Filip Daems through wide left, but his low cross was behind both De Jong and Patrick Herrmann.
Two minutes later, Herrmann pulled the ball back to Younes, whose shot was deflected wide for a corner.
From the set-piece, Gladbach took the lead with Thorben Marx heading the ball on at the far post to De Jong, who headed in from eight yards out.
Younes tried his luck from distance early in the second half when he saw Kevin Trapp had drifted off his line, but he missed the target considerably.
At the other end, Ter Stegen remained a spectator as Inui blazed a shot over his goal.
Gladbach continued to sit deep and break in numbers with Younes only just failing to get the ball through to De Jong as the Foals continued to pose the greater threat with their rare attacks.
Frankfurt then missed the chance to level in the last minute when Alexander Meier headed wide with practically his first sight of goal, which was too little, too late for the Eagles.