- Borussia Dortmund win 2-0 at Nuremberg in German Bundesliga
- Defending champions claim top spot from Bayern Munich
- Sebastian Kehl and Lucas Barrios score goals in freezing conditions
- Bayern can reclaim leadership with win at Hamburg Saturday
Reigning Bundesliga champion Borussia Dortmund took over top spot with a battling 2-0 win at Nuremberg Friday.
Goals from captain Sebastian Kehl and substitute Lucas Barrios in the second half gave Dortmund victory in freezing conditions.
The three points see them leapfrog Bayern Munich with 43 points from 20 games but the Bavarian giants can reclaim the leadership with a win at Hamburg Saturday.
Third-placed Schalke can also draw level on 43 points if they win at Mainz.
Borussia Moenchengladbach in fourth, a point further adrift, go to VfL Wolfsburg in a bid to step up their title challenge.
Dortmund coach Jurgen Klopp had to make an early change as midfielder Sven Bender was injured and replaced by youngster Moritz Leitner.
But it was the 19-year-old who played his part in Dortmund's opener early in the second half, starting the move that led to defender Lukasz Piszczek putting in Kehl to score on 48 minutes.
Barrios has been out of favor at the champions and wanted a move in the January transfer window but he came on for Poland's Robert Lewandowski to settle the match.
The Paraguay international netted from close range after Shinji Kagawa's shot had been pushed out.
Captain Kehl was delighted by his team's performance and going to the top for the first time since November.
"That was definitely a hard-fought victory," he told AFP.
"Nuremberg were very compact and didn't make it easy, so it was important we went 1-0 up when we did.
"I am also delighted that Lucas was able to score after attracting so many headlines this week. He has shown he still has the quality to help us."