I know Dortmund opponent is so weak so i am not surprised if they can able to win with big scores but this first match is good to restore their players fitness and Dortmund next match will be against another weak team Rot-Weiß Oberhausen on Wednesday that Dortmund at least will have 6 pre season matches before Bundesliga starting again and next month Dortmund will fight against Premier League Chelsea and Manchester United
Even though it's their first game, preseason games doesn’t always have to be played against tough opponents. Preseason games are merely held to put the team to the test to improve their match fitness level and help them gel, as well as to offer newly signed players a chance to contribute. The results don't really matter because some poor opponents even manage to defeat a strong side in a preseason game. They'll likely play a better squad before the preseason is up to see how emotionally and physically ready they are for the season.