Jurgen Klopp's side backed up Tuesday's 4-2 last 16, first-leg win in Russia to leap-frog Bayer Leverkusen, who crashed 1-0 at home to Mainz, their fifth straight defeat and eighth loss in 10 games.

"The team operated at a high level, which was necessary as Nuremberg began well and they had their chances," enthused Dortmund boss Klopp.

"The game has clearly answered all your questions," he added when waiting reporters failed to pose a single question.

Dortmund's Germany defender Mats Hummels celebrated his first game in four weeks after a foot injury by netting the opener at Borussia's Westfalenstadion.

Turkey midfielder Nuri Sahin fired in a free-kick and after Robert Lewandowski's header was saved, Hummels tapped home the rebound just after the break.

Poland star Lewandowski then scored his 15th league goal of the season by converting a superb pass from Henrikh Mkhitaryan on 64 minutes before the Armenia international netted his second goal in four days seven minutes from time.

Leverkusen's dreadful form continued with their fourth straight home defeat as Mainz moved up to sixth with their fifth win in eight games.

Ex-Liverpool star Sami Hyypia is facing a crisis as his Leverkusen side last won on February 1 and were also routed 4-0 at home to Paris Saint-Germain in the Champions League.

"My boys had tried to fight, but the belief and the ease was missing from our game," said the 40-year-old.

"If you don't score goals, it's hard to win a game."

Cameroon striker Eric Choupo-Moting slammed home the winner past Leverkusen goalkeeper Bernd Leno on 37 minutes after being set up by Stefan Bell.

Run-away league leaders Bayern Munich can go 20 points clear if they beat Schalke 04 at home on Saturday night.

Fourth-placed Schalke face the toughest test imaginable as they look to bounce back from their 6-1 drubbing at the hands of Real Madrid on Wednesday in the Champions League.

A horrendous error by Germany goalkeeper Marc-Andre ter Stegen cost Borussia Moenchengladbach their place in the top six following a 1-1 draw at bottom side Eintracht Braunschweig and left them winless in their last eight games.

Braunschweig gifted Gladbach a first-half lead when Iran goalkeeper Daniel Davari turned the ball into his own net with half an hour to go.

But Ter Stegen, who has been linked with a move to Barcelona next season, could only watch in horror as the ball spun into his own net after he failed to control a back pass from captain Filip Daems.

There was trouble before Werder Bremen's 1-0 win over Hamburg in the north German derby as the visitors' bus was pelted by Bremen fans, breaking a window.

Police used water cannons to separate rival fans outside Bremen's Weser Stadion and eight supporters were arrested.

After enjoying a winning debut in last Saturday's shock 3-0 win at home against Borussia Dortmund, which broke Hamburg's eight-match losing streak, new coach Mirko Slomka suffered his first defeat as his side remain third from bottom.

Bremen grabbed an early winner when Austria midfielder Zlatko Junuzovic fired home after a spectacular back heel from team-mate Aaron Hunt.

Hanover's Senegal striker Mame Diouf scored his first goal for a month in his side's 1-1 draw at Augsburg.