Union Berlin moved to the top of the Bundesliga on Sunday with a determined 1-0 win at Cologne.
Union, who are unbeaten this season, held reigning champions Bayern Munich to a draw last weekend.
The visitors began the game in Cologne at a furious pace, taking the lead on just four minutes.
Debutant goalkeeper Lennart Grill punted a long ball towards Jordan Siebatcheu, who passed to a running Sheraldo Becker on the edge of the box.
Becker's cross was deflected by Cologne defender Timo Huebers into the bottom corner of his own net.
Just four minutes later, referee Benjamin Cortus awarded Union a penalty for a handball, but Siebatcheu's tame effort was easily saved by Cologne keeper Marvin Schwaebe.
Becker had the ball in the back of the net again a minute afterwards, but his superb strike was ruled out for offside.
Despite dominating possession, Cologne were unable to find a way through with Union frequently dangerous on the counter.
Cologne went down to 10 men in the 81st minute when Luca Kilian picked up his second yellow card for a tactical foul on Andras Schaefer.
Cologne's first loss of the season leaves Union and Bayern as the only two unbeaten sides in the Bundesliga this term.
In Sunday's late game, Freiburg have the chance to retake top spot when they welcome Borussia Moenchengladbach to the Europa Park Stadion.