BERLIN (AFP) - Bayern Munich opened up a seven-point lead at the top of the Bundesliga on Sunday (Jan 25) with a 4-0 victory at bottom side Schalke 04 as Robert Lewandowski scored for the eighth straight league game.

Bayern extended their advantage over second-placed RB Leipzig, who suffered a shock 3-2 defeat at second-from-bottom Mainz on Saturday.

As the only top-three team to win this weekend, European champions Bayern are firmly on course for a ninth consecutive Bundesliga title.

Thomas Mueller claimed the first of his two goals with a header before Lewandowski netted from a tight angle midway through the second half for his 23rd goal in 17 league matches this season.

Bayern then scored twice in the final two minutes, with a second Mueller header before David Alaba smashed in a long-range shot in the 90th minute.

"We have had a few big points this week - even when we don't overrun the opposition," Mueller told Sky.

Bayern have taken a maximum nine points in the last week after a scrappy 1-0 win on Wednesday at Augsburg, who missed a late penalty, and a 2-1 home victory over Freiburg last Sunday.

Midfielder Joshua Kimmich weighed in with three assists in Gelsenkirchen.

Goalkeeper Manuel Neuer kept his 197th Bundesliga clean sheet to break Oliver Kahn's league record.

"I hope Schalke stay in the league and manage to turn the tide," said former Schalke player Neuer.

Schalke remain rooted to the bottom and 10 points from guaranteed safety.

However, Bayern coach Hansi Flick saw room for improvement.

"I wasn't completely satisfied. Sure, we scored four goals, but I also saw that we can do one or two things better in possession," said Flick.

"We sometimes play with too much risk, sometimes too slowly.

"Nevertheless, I'm satisfied with the nine points we got in one week."

Later, Hoffenheim jumped three places to 11th after their second straight win as Andrej Kramaric netted two penalties in a 3-0 home victory over Cologne, who remain in the bottom three.