Borussia Dortmund slumped to its fourth defeat in five Bundesliga games Saturday with a 2-1 loss at Cologne, while league leader Bayern Munich routed Werder Bremen 6-0.
Despite the return of key players from injury, Dortmund was unable to snap its five-game run without a win.
Kevin Vogt put Cologne ahead five minutes before the break, and though Ciro Immobile equalized three minutes after it, a mistake from goalkeeper Roman Weidenfeller gifted Simon Zoller the winner in the 74th.
Bayern captain Philipp Lahm and Mario Goetze both scored twice as Bayern warmed up for Tuesday's Champions League game at Roma with a comfortable win.
Stuttgart fought from three goals down to draw 3-3 with Bayer Leverkusen, Borussia Moenchengladbach defeated Hannover 3-0, Wolfsburg beat Freiburg 2-1, and Mainz beat Augsburg 2-1.
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