Jurgen Klopp has claimed that nerves played a leading role in Borussia Dortmund's late collapse in the 2-1 defeat away to Bayern Munich on Saturday.

Dortmund looked on course to end a four-game Bundesliga losing streak at the Allianz Arena after Marco Reus fired the visitors into a first-half lead over the champions.

However, Robert Lewandowski bagged a 72nd-minute equaliser against his former club, while Arjen Robben converted a penalty four minutes from time to complete the comeback.

"It was close. It was a good first half and a less good second, in which we buckled to the pressure," manager Klopp told reporters.

"We deserved something for the first half but not for the second. We've invested a lot but got nothing in return, and that's what we have to worry about.

"But many congratulations to Bayern on a deserved win."

Klopp's side stay 16th in the German top flight, having not won in seven outings.