By Karolos Grohmann
BERLIN (Reuters) - Borussia Dortmund have shown two faces this season, with their lacklustre domestic form in stark contrast to their scintillating European run, which they hope to extend against Benfica in the Champions League round of 16 on Tuesday.
With just two wins from their past seven Bundesliga games, Thomas Tuchel's team have long dropped out of the title race and Saturday's shock 2-1 loss to bottom side Darmstadt 98 left them 15 points adrift of leaders Bayern Munich.
But the Ruhr valley club have been sensational in the Champions League, thriving on the big stage and scoring a record 21 goals to top their group ahead of Real Madrid.
The 1997 European champions and finalists four years ago will be hoping they can replicate that form for their first leg in Lisbon.
"In our two matches against Leipzig (league) and Hertha Berlin (German Cup) we played two matches where we were in the spotlight," Tuchel said after the loss to Darmstadt. "That's when we seem to be focused best and sharp and that's when we reach our maximum."
"Against Darmstadt 98 there was nothing to win. The game was under the radar and everyone expected us to do so. It seems we have trouble being really sharp at games without the big stage."
There are few bigger football stages than Benfica's iconic Estadio da Luz but Tuchel's biggest concern remains Dortmund's backline which has proved shaky throughout the season.
Forwards Pierre-Emerick Aubameyang and Marco Reus have provided a constant stream of goals but keeping a clean sheet has proved far trickier.
Frailty at the back was evident again on Saturday when Darnstadt twice outsmarted defenders, leaving Dortmund to wonder how they lost the game.
"This will be a completely different game. The Champions League anthem alone makes it different," said Dortmund keeper Roman Buerki.
Benfica's dress rehearsal was far more successful as the Portuguese look to reach the quarter-finals for the third time in the past six seasons.
They beat Arouca 3-0 on Friday to remain top of the Portuguese league, ahead of rivals Porto, and earn an extra day's rest over the Germans.
Greece international forward Kostas Mitroglou made it 12 goals in as many games while Andre Carrillo scored for the first time since August.
They will be without suspended Serbian Andrija Zivkovic when they host the Germans but, with four wins in the past five matches, they could not have wished for better form going into the game.