Hamburg dented Borussia Dortmund's title hopes with a 3-1 win on Friday in a Bundesliga clash which started 15 minutes late due to heightened security measures following the Paris terror attacks.
Goals from Pierre-Michel Lasogga, Lewis Holtby and a Mats Hummels own goal sealed the three points for Hamburg who moved up to eighth in the table while defeat left Dortmund facing the prospect of slipping eight points behind leaders Bayern Munich by the end of the weekend.
Hamburg coach Bruno Labbadia was delighted with his team's performance. “We didn't let them come too far forward and we stayed true to our tactics. It is never easy against Dortmund, they are a great side,” he said.
Dortmund goalkeeper Roman Burki said the performance was his team's worst of the campaign. “We just weren't as aggressive as them. That's the worst game we have played this year - we will have to see where to improve,” said the keeper. “We had won seven matches in a row before this game, so all we can do is go back and try and make it better.”
The start of Friday's game was delayed for safety reasons, adding to the tension just three days after a bomb scare caused Germany's friendly with the Netherlands in Hannover to be postponed.
Heavy traffic outside Hamburg's Volksparkstadion, as well as tightened security checks being carried out in the aftermath of last Friday's Paris attacks which killed 130 people, caused the 1930GMT kick-off to be put back.
The German team had experienced first-hand the events in Paris when suicide bombers blew themselves up outside the Stade de France where the world champions were playing France.
With a giant French tricolour flying outside the stadium on Friday, fans and VIPs - including German legend Uwe Seeler - were patted down by security guards. Both sides, wearing black armbands, and 57,000 fans then observed a minute's silence before the kick-off to remember the Paris victims.
On the pitch, Hamburg were ahead after 19 minutes against their fellow former European champions.
Ivo Ilicevic was brought down by Dortmund's Swiss goalkeeper Roman Burki who was booked for his troubles. Up stepped Lasogga to fire the penalty into the corner for his sixth goal of the campaign.
At the other end, prolific Dortmund striker Pierre-Emerick Aubameyang, who went into the game as the Bundesliga's joint-leading scorer with 14 goals, was having a low key night as were his teammates.
By half-time, Hamburg were 2-0 ahead when Nicolai Mueller broke away from his markers before finding Holtby who scored past Burki in the left-hand corner.
Aubameyang missed the target early in the second half with a chip with the outside of his boot although Marco Reus, in space, was screaming for a pull-back.
Dortmund skipper Hummels did put the ball in the net in the 55th minute with a fine, close-range header. Sadly for his team, it was an own-goal as Hummels misdirected a Hamburg corner past a stunned Burki.
Hamburg keeper Rene Adler was then called into action to deny Aubameyang from close range and was then quick to smartly dive to his left to keep out a fierce free-kick from Ilkay Gundogan.
Aubameyang pulled a goal back three minutes from time and had another ruled out for offside but Hamburg were worthy winners on the night.