Borussia Dortmund have lost for the fourth time in the Bundesliga season after suffering a 1-0 defeat to Hamburger SV, who have won for the first time since the start of the new campaign.
The visitors offered an early sign of how difficult the afternoon would be for Dortmund when Nicolai Muller dragged a shot just wide after latching on to a loose ball in the box.
In a first half when clear opportunities were rare, Kevin Grosskreutz came closest to scoring for the home side with a curled effort which drifted just wide of the post.
Pierre-Michel Lasogga struck the crucial blow nine minutes before the break when he fired into the bottom corner after collecting a clever through-ball from Muller.
Milos Jojic was introduced by Jurgen Klopp at the start of the second half, and should have equalised with one of his first touches, but he could only send a wayward effort wide from just inside the box.
Despite seeing Dortmund dominate possession for long periods, the better chances were falling for the visitors, but Roman Weidenfeller ensured that his side didn't fall further behind by pushing away Lasogga's header.
Inevitably, a spell of Dortmund pressure did arrive, but Jaroslav Drobny frustrated the hosts by keeping out a powerful header from Adrian Ramos.
Another great chance fell to Dortmund late on when substitute Ciro Immobile sliced just wide of the post, and they would go no closer to claiming a point in the closing stages.
