Dortmund did not manage to get a win in their friendly game against valencia, and they lost with such a large score 3 1 and they only managed to score from the penalty spot, its not looking good for dortmund i guess we will see bayern a champion once again.
You shouldn't take friendlies too seriously. Of course, the score is important, but it should not be forgotten that there are matches to try whether the team is ready or not. So even though they lost 3-1 to Valencia, it's too early to say it's over for Borussia. Bayern Munich will most likely be champions as always, but Dortmund will do their best.