Thomas Tuchel has admitted that he was "horrified" by the way in which Borussia Dortmund began their 4-3 Europa League playoff victory at Odd tonight.

The first leg in Norway threw up a see-saw encounter in which Tuchel's men recovered from a three-goal deficit to earn a slender advantage in the tie.

Dortmund, beaten Champions League finalists in 2013, were three down inside 22 minutes, before a rousing second-half display saw them bring four away goals back to Signal Iduna Park next Thursday.

"We weren't prepared for what happened at the start, mentally we were not strong enough," he told reporters.

"I was horrified, at how easy we fell and conceded the goals. It will need to be much better.

"But we showed morale in the second half, and I am pleased for that. In the end we deserved the win, and actually the score was too low on our part."

Pierre-Emerick Aubameyang kick-started the comeback on 37 minutes, before finishing it in the final quarter after Shinji Kagawa added a second.

Henrikh Mkhitaryan then struck the winner with five minutes remaining to snatch the victory.