Bayern Munich continued their unbeaten start to the Bundesliga season with a 2-0 win over Freiburg on Tuesday night.
Mainz's winless run in the Bundesliga stretched to eight games as they came away from Cologne with just a point.
Schalke suffered their first home defeat under Roberto Di Matteo as Cologne claimed a precious 2-1 win.
Bayern Munich remain seven points clear at the top of the Bundesliga after a 1-0 home win over Bayer Leverkusen.
Augsburg moved into contention for a Champions League berth next season with a 2-1 win at Cologne.
Bayer Leverkusen turned it on in the second half to claim a 5-1 victory in the Rhineland derby against Cologne.
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