Borussia Dortmund's four-game winning streak in the Bundesliga came to a halt as they were beaten 2-1 away to RB Leipzig on Saturday.
French winger Christopher Nkunku put Leipzig in front in the 29th minute to score for the second game in a row after netting in Wednesday's 2-2 draw with Paris Saint-Germain in the Champions League.
Jesse Marsch's side missed numerous chances to build on their lead before they were punished by a Marco Reus equaliser early in the second half.
Leipzig quickly set about restoring their lead, with Nkunku hitting the post and Dortmund keeper Gregor Kobel making an outstanding double save to thwart Mohamed Simakan and then boot the loose ball away before forward Dominik Szoboszlai could pounce.
They eventually took advantage of their dominance when Yusuf Poulsen slid to the floor to send a cross from Nkunku inside the near post in the 68th minute.
Defender Nordi Mukiele had a headed goal disallowed later on for offside for the hosts but Poulsen's strike was enough to secure a first win for Leipzig over Dortmund in over four years.
The result left second-placed Dortmund on 24 points after 11 games, four behind Bundesliga leaders Bayern Munich who beat Freiburg 2-1 at home earlier on Saturday.