Champions Bayern Munich crushed Werder Bremen 6-0 in the Bundesliga to protect their four-point lead at the top as last season's runners-up Borussia Dortmund continued their poor run with a 2-1 loss at Cologne.

Fellow Champions League participants Bayer Leverkusen spectacularly imploded, giving up a 3-0 halftime lead to draw 3-3 against troubled VfB Stuttgart.

With winger Franck Ribery making his comeback as a substitute on the hour, league leaders Bayern were in complete control with Philipp Lahm and Xabi Alonso giving them an early two-goal cushion.

With Werder unable to counter the Bavarian attacks, a 43rd-minute penalty from Thomas Mueller and Mario Goetze's shot two minutes later killed off the game before halftime.

Lahm and Goetze got their second goals of the afternoon in the second half to lift Bayern to 20 points, four ahead of second-placed Borussia Moenchengladbach, who eased past Hanover 96 3-0 with two goals from forward Max Kruse.

Dortmund, who travel to Galatasaray in the Champions League next week, drop to 14th on seven points after their third consecutive defeat. They are now just three points above bottom club Bremen.

Top-scorers:

6 - Mario Goetze (Bayern Munich)
5 - Max Kruse (Borussia Moenchengladbach)
     Shinji Okazaki (Mainz)
4 - Karim Bellarabi (Bayer Leverkusen)
     Son Heung-Min (Bayer Leverkusen) 
     Robert Lewandowski (Bayern Munich)
     Alexander Meier (Eintracht Frankfurt)
     Tarik Elyounoussi (Hoffenheim)
     Franco Di Santo (Werder Bremen)

Source: Reuters