Napoli made it three wins out of three for Italian sides in the Europa League on Thursday night with a 2-0 victory at Legia Warsaw.
Robert Lewandowski carved his name in history with a double for Bayern Munich, while Schalke drew level with Dortmund.
Dortmund lost ground on Bayern Munich at the top of the Bundesliga on as they dropped points for the first time this season.
Borussia Dortmund returned to the top of the Bundesliga with a 3-0 victory over Bayer Leverkusen on Sunday.
Schalke and Werder Bremen made moves up the Bundesliga on Sunday with wins over Mainz and Hoffenheim, respectively.
Wolfsburg have signed German international midfielder Julian Draxler from Schalke on a five-year contract.