Davie Selke scored the winner to secure Cologne a much-needed 1-0 win over Darmstad for just their second Bundesliga victory of the season.
The result will also keep Cologne out of the relegation zone at least until Saturday evening.
Selke finished off a corner in the 60th minute to score the only goal of the match.
Cologne thought they had another one in the 66th, but Luca Waldschmidt's effort from close range was ruled out by video assistant review (VAR).
The VAR was again in action in the 71st, this time to deny Darmstadt a penalty that could potentially secure them a point.
"It was really important to win this game," Selke told broadcasters DAZN.
Darmstadt are also fighting against relegation and with the defeat entered the drop zone.
"It's a fight against relegation and we said ourselves we wanted to talk less and do more. It (the win) is extremely important to all of us," Selke added.
Champions Bayern Munich host bottom-of-the-table Union Berlin on Saturday, while leaders Bayer Leverkusen welcome Borussia Dortmund on Sunday.
Australian Associated Press