Lucien Favre bemoaned Borussia Dortmund's impatience after they stunningly fell victim to Union Berlin in the capital club's maiden Bundesliga win on Saturday.

Marius Bulter scored twice as Union broke their top-flight duck with a shock 3-1 win over last term's runners-up.

Bulter's first-half strike was quickly cancelled out by Paco Alcacer, but the former scored again five minutes after the interval and Sebastian Andersson then added a third for the Bundesliga new boys.

"I think we thought it would be like the second half in Cologne. That was not the case," said Dortmund head coach Favre, referencing last Friday's match in which his side trailed 1-0 at the interval but triumphed courtesy of three goals in the final 20 minutes.

"We have to keep our patience and not play hastily with the score at 1-1; we have to defend very well. This is very important.

"Instead, we have lost our patience [and conceded] an unnecessary goal.

"Even then, we should have kept patient. There was still time to make it 2-2 and maybe win the game as well. Our second half was not good."