Werder Bremen on Sunday failed to make up any ground on the Bundesliga leaders as they slumped to a 2-1 home defeat against Arminia Bielefeld, dpa reported.
The other game on Sunday saw goals by Christian Fuchs and Diego Klimowicz give VfL Bochum a 2-0 victory at home against Karlsruhe that allowed them to escape the relegation zone.
In Bremen a weakened Bremen side who were missing star midfielder Diego and striker Claudio Pizarro through suspension, as well as several other injured players, went behind in the 24th minute as Thorben Marx slipped the ball past goalkeeper Tim Wiese.
Portuguese striker Hugo Almeida grabbed an equalizer a minute from the break with a well-taken free-kick and Bremen fans were hoping for a much better performance in the second half from their side, but they were to be disappointed.
The Bremen defence, where coach Thomas Schaaf had to replace four injured players, looked weak and it was a Bremen mistake that gifted Bielefeld their second goal four minutes after the restart.
Bremen captain Torsten Frings unnecessarily lost the ball in his own half to Zambian Christopher Katongo, who passed the ball into the middle where Artur Wichniarek was on hand to score his 11th of the season.
Bremen enjoyed more of the possession throughout the second half - as they did in the first - but failed to create any real opportunities to score a second goal against a team that they had managed to beat 8-1 at home last season.
Bielefeld coach Michael Frontzeck complimented his side after the win. "We really fought well. I think at the end of the day we deserved the victory because of our effort.
"The best thing is that hopefully this will put an end to all this discussion about us not having won a game away from home for 63 matches."
Wichniarek said that his side could not be expected to go into a game in Bremen playing offensive football.
"Bremen is a good side, you have to make your game from the back and we did that. We stood firm at the back and I think that made the difference."
Surprise leaders Hoffenheim continue to top the table after beating Energie Cottbus 2-0 at home on Saturday. The Bundesliga rookies have a two point cushion after SV Hamburg managed to beat Bayern Munich 1-0 on Friday night - a result that saw Hamburg climb to third, while the champions slipped down to fourth.
Hertha Berlin are second after a hard-fought 2-1 victory against Eintracht Frankfurt in the capital.
At the wrong end of the table, Borussia Moenchengladbach, Energie Cottbus and Karlsruhe occupy the relegation places, while Bochum are now 15th with 14 points, one point more than Cottbus and Karlsruhe.