Cologne scored twice in the final six minutes to turn a seven-goal thriller in their favour and claim their first victory of the season by beating Hamburg 4-3.
The game continued to swing to and fro as Hamburg restored their advantage with two goals in three minutes from Slobodan Rajkovic and Son Heung-Min, but Christian Clemens and Kevin McKenna secured victory for Cologne.
Hamburg went close to an opener in the tenth minute but Heiko Westermann struck the crossbar. But they were awarded a penalty just seconds later as Cologne captain Geromel took down Dennis Aogo on the left side of the box, and Petric stepped up to beat Cologne goalkeeper Miro Varvodic and find the bottom right corner.
Cologne equalised when Slawomir Peszko's cross from the left beat Hamburg keeper Jaroslav Drobny and Chihi finished first time into the empty goal.
Cologne refuse to give up
Cologne introduced Lukas Podolski at the break and the move paid off almost immediately as the Germany international crossed from the left to the inrushing Novakovic, who struck to make it 2-1.
Hamburg equalised ten minutes later as new signing Rajkovic converted the rebound after Son's header hit the right post. And Son got on the scoresheet himself after 62 minutes to give Hamburg a 3-2 lead, running onto a long ball down the right side before cutting inside and finishing across Varvodic.
Cologne appeared to be beaten but they equalised after 84 minutes from a set-piece as Clemens converted Mato Jajalo's corner.
And the visitors grabbed the three points four minutes later when Drobny beat away a free-kick straight to McKenna, who blasted into the empty goal. The defeat leaves Hamburg with just one point from their opening four games.