Borussia Dortmund’s up and down season continued on Saturday in the form of a 2-1 defeat at Union Berlin which prompted sharp criticism from sporting director Sebastian Kehl. It was the second time in as many weeks that victory in the Champions League was followed by defeat in the Bundesliga where Dortmund are without victory away from home in five matches and have conceded 11 goals in four games. Ten points from six matches are their worse start into a Bundesliga season in a decade and far from the ambition to challenge for the title they last won in 2012 and threw away on the last matchday i…