Borussia Dortmund goalkeeper Mitchell Langerak has insisted that his side cannot hide behind Roman Weidenfeller's red card for the reason they lost 2-1 to Napoli in the Champions League Group F.

Langerak came on after Weidenfeller was sent off for handling outside the area, but could not stop Lorenzo Insigne's free kick that ultimately proved to be the winning goal.

"To play your first game is always difficult, and away to Napoli is even harder," Langerak told UEFA.com. "We wanted to come away with something today but to come on like that, it's a bit difficult.

"Obviously losing [Jurgen Klopp] and losing Roman to the red card was a setback for us but it's no excuse.

"I think we did quite well in the second half to come back and make it an interesting game, which was important for us, but with 10 men for 45 minutes makes it more difficult. We can come away thinking positively about the game."

Dortmund's next Champions League game is at home to Marseille on October 1.