Borussia Dortmund have suffered back-to-back defeats under Thomas Tuchel for the first time by slipping to a 1-0 reverse at FC Krasnodar.
BVB fell behind to Pavel Mamaev's second-minute penalty and were unable to drag themselves level in the Europa League group-stage clash.
Despite the setback, Dortmund - without key players Marco Reus and Pierre-Emerick Aubameyang this evening - are still guaranteed a spot in the knockout stages.
Mats Hummels was at fault for the concession of the spot kick, pulling back on Mamaev who tucked away to score what would prove to be the game's only goal.
Tuchel's men, still reeling from a 3-1 loss at Hamburg last Friday, bounced back well after their early concession but could not quite draw themselves level at the Kuban Stadium.
Ilkay Gundogan and Jonas Hofmann both came close to equalising, before Adrian Ramos saw his attempt come back off the crossbar in the best opening of the first half for his side.
Dortmund continued to ask most of the attacking questions following the restart, almost finding a breakthrough instantly when Marcel Schmelzer fired a half-volley wide of the target, before Lukasz Piszczek glanced a header wide.
Then came another big moment in the match as a Krasnodar player headed against their own bar, while Ramos squandered a glorious chance at the back post to see BVB's frustrations grow.
Despite the Bulls' efforts it should have been all square when Gundogan looked certain to fire a way through 15 minutes from time, only for Charles Kabore to dive in front of the shot to prevent a sure-fire equaliser.
Roman Weidenfeller did have to pull off one last big stop to deny the home side bagging a second, however, as the Russian outfit held out for a famous win.