Hannover players celebrate the only goal of the game.

Patrik Stollarz Getty Images

Leon Andreasen's controversial hand-ball goal and some excellent goalkeeping from Ron-Robert Zieler combined to give Hannover 96 an upset 1-0 victory at 1. FC Köln Sunday afternoon, putting a temporary halt to the home side's best-ever Bundesliga start.

The goal that shouldn't have been came in the 38th minute and prevented Köln from climbing into fourth place in the Bundesliga. Instead Peter Stöger's side dropped to sixth in the race, falling behind Hertha BSC Berlin on goal-difference as they lost for the first time at home since last December.

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Hannover won for just the second time this season to put some distance between themselves and the relegation zone, but they remain 14th, just ahead of slumping Werder Bremen.

Hannover's goal should have been disallowed, replays clearly showing that Andreasen used his forearm to turn in a Timo Horn parry to the header-on from Christian Schulz. Hiroshi Kiyotake's corner on the right split the home defense to create the chance. Referee Bastian Dankert missed the hand ball and was deaf to the vehement protests from goalkeeper Horn and his defenders.

Whether the Dane could have simply run into the ball and bodied it into the net will never be known. Instead, as Horn got a hand onto the dipping header from Schulz, he succeeded only in directing the ball into the scorer's path. From behind, Andreasen may have appeared to nudge the ball home with his thigh, but replays from behind the goal showed the forearm swing and will not be enjoyed by referee Dankert when he sees the video.

Köln struggled to get its attack in gear, failing to find front-runner Anthony Modeste consistently. Marcel Risse did bring a good save from Zieler in the opening half, but the visitors kept a tight lid on Modeste and Leo Bittencourt, usually the fulcrum for the Billy Goats.

Modeste had his first real chance in the 65th minute when he twisted acrobatically to put a header on net from a Bittencourt cross, Zieler going down smartly at the post to keep the ball out. The home side then wanted a penalty in the 69th minute when Salif Sane slid to block a cross, but this time the replays showed that Dankert got it right. Sane blocked the ball with his body rather than a hand.

Substitute Philipp Hosiner missed the best opportunity to get Köln level in the 75th minute when he could not beat Zieler from point-blank range. The German international keeper got his foot onto the shot that probably should have been the equalizer. Zieler had to make one more one-handed save off Modeste in the 87th minute then could only look on fortunately as Frederik Sorensen flashed an open header wide of goal off the resulting corner, then one-handed a last chance away from Modeste in stoppage time.

Ingolstadt had the opportunity to move into fourth place when they kicked off at last-place VfB Stuttgart in the Sunday night match.