Union Berlin, however, are only looking upwards after moving into fifth place in the table with a thumping 5-0 win over Arminia Bielefeld prior to the international break.
Having lost their opening four games of the season, Koln's results and performances have both picked up in recent weeks, with Markus Gisdol's side drawing three of their last four matches and only marginally losing 2-1 to Bayern Munich in the other match in that run.
The most recent of those results came in a 1-1 draw at Werder Bremen prior to the international break, with Gisdol disappointed that his side could not hold onto their lead. After losing goalkeeper Timo Horn to injury in the first half, Ondrej Duda's free kick was inadvertently turned into his own net by Bremen captain Niklas Moisander to hand the struggling visitors the lead.
However, a clumsy handball saw Koln concede their fifth penalty in seven league matches already this season, with former Koln player Leonardo Bittencourt duly dispatching from the spot. In the end, Koln were perhaps grateful to walk away with a point after Joshua Sargent's tame header sailed into the hands of Horn's replacement Ron-Robert Zieler late in the game.
Still looking for their first league win of the season, Gisdol and his players will be hoping it finally arrives this weekend, but it will certainly not be easy against an in-form Union Berlin side.
Indeed, Urs Fischer's side are flying at present, having taken 12 points from their last six league matches to remain unbeaten since losing on the opening day of the season.
Having survived relegation in their first ever top flight campaign last season, the 5-0 win over Arminia Bielefeld saw them reach new heights last time out. It was little surprise to see Max Kruse at the heart of everything, with the 32-year-old one of the stand-out players of the Bundesliga season so far. He surely cannot be too far away from a first call-up to the German national team squad since 2015.
Kruse's through-ball for Sheraldo Becker was timed to perfection, with the onrushing winger adjudged to have been marginally onside before squaring the ball for Keita Endo to open the scoring in only the third minute. Robert Andrich doubled his side's lead with a powerful first-time strike from the edge of the area after Kruse's excellent pull-back, before Kruse once again found Becker, who this time elected to shoot to give Union Berlin a 3-0 lead heading into the break.
After Amos Pieper brought down Akaki Gogia in the penalty area in the 52nd minute, Kruse was presented with the chance to dispatch his 16th Bundesliga penalty from 16 attempts and duly obliged. With only a few minutes remaining, Gogia's delightful scooped through ball found Cedric Teuchert to put even more gloss on an outstanding victory, and take Fischer's side to the heady heights of fifth place in the table.
FC Koln Bundesliga form: LLDDLW
Union Berlin Bundesliga form: DWDDWW
Veteran forward Anthony Modeste, meanwhile, is doubtful due to a back issue, but Horn should be fit to start in goal after shaking off his hip injury sustained against Bremen.
Fischer may choose to bring Teuchert into the side for the injured Pohjanpalo after the French forward scored late on against Arminia.
FC Koln possible starting lineup:
Horn; Wolf, Bornauw, Czichos, Katterbach; Limnios, Duda, Ozcan, Drexler, Jakobs; Andersson
Union Berlin possible starting lineup:
Luthe; Trimmel, Friedrich, Knoche, Lenz; Gentner, Andrich; Becker, Kruse, Endo; Teuchert
We say: FC Koln 1-2 Union Berlin
Despite losing four of their seven matches this season, Koln have been competitive in every match and we expect no different here.
However, with Kruse in his most impressive form for years and Union Berlin playing some very impressive football in recent weeks, Fischer's side could have the edge.