Lukas Podolski and Milivoje Novakovic each netted a brace as Cologne gave their Bundesliga survival hopes a further boost with a convincing 4-2 victory over Mainz.
Frank Schafer's side, who stunned champions Bayern Munich 3-2 last weekend, were quick off the mark and one up through Podolski after just three minutes and, although Sami Allagui levelled, Novakovic soon restored Cologne's lead.
Podolski and Novakovic were each on target again in the second half to seal another impressive victory - and lift Cologne out of the drop zone - despite a late consolation from Mainz substitute Petar Sliskovic.
Werder Bremen remain in a precarious position at the bottom end of the Bundesliga table after only managing a 1-1 draw against Hannover at the Weser Stadion.
Didier Ya Konan, who was only passed fit to play this morning, put Hannover in front in the 26th minute, but Per Mertesacker salvaged a point for Bremen with his goal five minutes into the second half.
Defeat would have seen Bremen fall into the bottom three, but the point was enough to take them above both Wolfsburg and Kaiserslautern into 14th position.