In form Ellyes Skhiri scored a second-half brace as Cologne stunned Eintracht Frankfurt 3-0 at home in the Bundesliga on Sunday.
Skhiri's goals, coming from a header and a half-volleyed smash, took the Tunisia midfielder to five league goals for the calendar year, the most in the Bundesliga.
Frankfurt had the better of the first half and almost scored twice through man-of-the-moment Randal Kolo Muani.
The France striker's shot was intercepted after 24 minutes and he had a chance to open the scoring with 39 minutes gone but was thwarted thanks to some desperate defending from Julian Chabot.
Cologne broke the deadlock early in the second half through centre-back Timo Huebers, who headed in a cross from Austrian midfielder Florian Kainz.
Cologne doubled their lead with 20 minutes to go through Skhiri, who headed in a fortunate rebound from another home side counter attack.
Skhiri added another in the 86th minute, driving in a half-volley from near the penalty spot for his fifth goal of 2023 in all competitions.
The victory took Cologne, who resumed after the winter break near the relegation places, up to 11th.
Frankfurt, who came into the match unbeaten in 2023, missed the chance to climb into the top four and now sit sixth after 20 matches.
HERTHA HAPPY
Hertha Berlin defender Marton Dardai unleashed a long-range stunner to help drag his side out of the relegation places with a 4-1 home win against Borussia Moenchengladbach.
Dardai, the son of former Hertha player and coach Pal who sat watching in the stands, rocketed a low drive off the underside of the crossbar early in the second half to put his side 2-1 up on his 21st birthday.
The win was just Hertha's second victory in their past nine games, taking the side past Stuttgart and out of the bottom two automatic relegation places.
The home side, who had conceded 13 goals and scored just one in their past four matches, looked in for another long day when Gladbach took the lead after 17 minutes.
Swiss centre back Nico Elvedi rose high to head in a corner from Luca Netz, giving the visitors the lead.
Hertha equalised after 30 minutes through local junior Jessic Ngankam, who scored his first goal for the club he has represented since the age of six.
Despite the attention of five Gladbach defenders, Ngankam latched onto a pass from Marco Richter and buried it past 'keeper Jonas Omlin.
Dardai struck after 52 minutes to bring the home crowd to their feet, including his father who started with Hertha in 1997 and has been involved with the club as a player and later a coach since.
France striker Marcus Thuram had a chance to rescue a point for Gladbach with just three minutes remaining, but his strike was tipped over the bar by Oliver Christensen.
Another Berliner, striker Derry Scherhant, scored third in injury time before Belgian winger Dodi Lukebakio added a fourth from the spot, helping Hertha to just their fourth win of the season.