Robert Lewandowski netted twice on his 100th Bundesliga game for Bayern Munich as they beat Mainz 4-0.
Carlo Ancelotti praised Bayern Munich's performance as the German champions returned to winning ways in the Bundesliga with a 4-0 win over Mainz.
United States forward Bobby Wood missed Hamburg's Bundesliga defeat at promoted Hannover on Friday because of a reported knee injury.
Promoted Hannover defeated injury-hit Hamburg 2-0 at home in the "little northern derby" to maintain their fine start to the Bundesliga on Friday.
Dortmund love to play attacking football and while they may get away with throwing numbers forward against Koln, it remains a risky game to play.