Mainz rallied to beat promoted Kaiserslautern 2-1 on Sunday and join Hoffenheim at the top of the Bundesliga as the only teams with perfect records after three rounds.
Srdjan Lakic scored after 20 minutes for Kaiserslautern but Niko Bungert and Andre Schuerrle turned the game around with goals in the 71st and 73rd.
Kaiserslautern fell to its first defeat, while Mainz moved even on nine points with Hoffenheim.
Cologne won its first game of the season by edging promoted St. Pauli with a goal in the 17th minute by Taner Yalcin.
Lukas Podolski hit the post with a powerful shot from more than 20 meters (yards) and Yalcin pounced on the rebound to send the ball back into the net.
St. Pauli had a goal disallowed for offside late in the game and missed a clear opportunity in stoppage time.
In Mainz, the home side conceded the goal moments after Christian Fuchs had hit the post. Lakic collected a long pass and easily scored.
But Mainz beat an offside trap and had three players in front of Kaiserslautern's goal before Bungert scored from close range.
Schuerrle shot from outside the penalty area to secure the victory two minutes later.
