Bayer Leverkusen wasted a chance to close the gap on Bundesliga leader Bayern Munich after being held to 0-0 at Freiburg on Saturday.
Andre Schuerrle came closest to scoring for second-place Leverkusen in a hard-fought game, crashing his shot against the post in the 71st minute. Oliver Baumann pulled off a fine save to deny the Germany international shortly afterward.
''We knew we'd have it difficult against Freiburg,'' Schuerrle said. ''They made it hard for us, put us under a lot of pressure and fought for every ball.''
The draw means Bayern can open an 11-point gap at the top with a win at Stuttgart on Sunday.
Schalke was held to 0-0 at relegation-threatened Augsburg, leaving coach Jens Keller under increasing pressure.
''You can't be happy with that but you have to live with it,'' Keller said. ''Augsburg was very aggressive. We didn't get into the game and didn't win the ball to get our strikers into a position to score.''
Mainz took full advantage with a 3-0 win at bottom side Greuther Fuerth to move fifth, one point above Schalke.
Around the Bundesliga
Elsewhere, Borussia Moenchengladbach stretched its unbeaten run to nine games across all competitions with a 2-1 win at home over local rival Fortuna Duesseldorf.
Hannover beat Wolfsburg 2-1 in another local derby, despite playing most of the game with 10 men after Sebastien Pocognoli was sent off on his Bundesliga debut.
Eintracht Frankfurt consolidated fourth place with a 2-1 win at home over troubled Hoffenheim, which slipped into the relegation zone.
Hoffenheim, which sent experienced defender Marvin Compper to train with its youth team during the week, had Tim Wiese to thank for two important saves early on, when Frankfurt also hit the post and had a goal ruled out.
Martin Lanig lifted the ball over Wiese to score in the 35th, after Takashi Inui sprung the offside trap.
Kevin Volland equalized in the 65th, but Stefan Aigner restored Frankfurt's lead three minutes later after Wiese failed to deal with a corner.
''I'm simply happy that we won,'' said Frankfurt coach Armin Veh. ''The whole team fought well.''
Moenchengladbach endured a shaky start to the season but appears to have found stability at last. Lucian Favre's side got off to a great start in the sixth minute when Fortuna defender Juanan was unfortunate to deflect Oscar Wendt's cross into his own goal, and Luuk de Jong crossed for Patrick Herrmann to make it 2-0 eight minutes later.
Dani Schahin pulled one back from the penalty spot in the 50th, when De Jong was adjudged to have handled the ball, but the visitors were unable to capitalize on their improvement from the first half.
In Hannover, striker Mohammed Abdellaoue opened the scoring in the third, when he beat Simon Kjaer on the right, advanced and then curled a delightful effort inside the far post.
Winter signing Pocognoli was sent off for a high-footed challenge on Fagner in the 34th, yet Mame Biram Diouf made it 2-0 four minutes later when the ball rebounded off his shoulder and in after he struck the post with his initial effort.
Alexander Madlung scored what proved to be a consolation just after the break.
''Of course it's frustrating,'' said Dieter Hecking after his first return to Hannover as Wolfsburg coach. ''We played an excellent game but were undone by Hannover's brutal efficiency.''
