Hoffenheim stumbled to a 2-1 defeat at Wolfsburg on Sunday as all six clubs chasing Bayern lost over the weekend.
Bundesliga leaders Bayern Munich saw their winning run come to an end as Schalke battled to a 1-1 draw at the Allianz Arena.
Neven Subotic has joined Cologne on loan from Borussia Dortmund until the end of the season.
Hoffenheim suffered their first Bundesliga defeat of the season as they went down 2-1 at RB Leipzig.
Hakan Calhanoglu scored twice as Bayer Leverkusen beat Hertha Berlin 3-1 on Sunday to move up to eighth in the Bundesliga.
Bayern Munich moved above Leipzig at the top of the Bundesliga, 11 days before the top two are due to meet at the Allianz Arena.
Bayern Munich bounced back from defeat to Borussia Dortmund a week ago with a 2-1 win at Bayer Leverkusen to stay second in the Bundesliga.
Cologne and Hertha Berlin both closed the gap on Bayern Munich after their defeat to Borussia Dortmund.
Bayern Munich started the defence of their DFB-Pokal title with a 3-1 win over Augsburg in the second round on Wednesday.
Bayern Munich moved three points clear at the top of the Bundesliga on Saturday after seeing several of their rivals stumble.
Bayern Munich's 100 per cent Bundesliga record was brought to an end by Cologne, who drew 1-1 at the Allianz Arena.
Oliver Burke scored his first Bundesliga goal to help Leipzig extend their unbeaten start to the season with a 1-1 draw in Cologne.
Cologne extended their unbeaten start to the season and moved top of the Bundesliga with a comfortable 3-0 win over Freiburg.
Leipzig picked up a first Bundesliga win in their maiden home fixture with a 1-0 win over Borussia Dortmund, while Leverkusen beat Hamburg.
Borussia Dortmund respond to Bayern Munich with opening day win thanks to Pierre-Emerick Aubameyang's double.
Augsburg moved a step closer to Bundesliga survival following a goalless draw with 10-man Cologne on Friday.
Bayern Munich beat Hertha Berlin 2-0 to move a step closer towards the Bundesliga title, while Borussia Dortmund defeated Stuttgart 3-0.
Borussia Dortmund recovered from their shock Europa League defeat to Liverpool with a 3-0 win over Hamburg in the Bundesliga.
Bayern Munich remain on course for a record-breaking fourth successive Bundesliga title with a 3-1 victory at Stuttgart.
Germany defender Jonas Hector has suggested he could be tempted to leave FC Koln for Liverpool.