Dortmund were looking to bounce back from their 5-2 midweek defeat by Real Madrid in the Champions League and they made an ideal start when Donyell Malen finished coolly inside the penalty area.
The Netherlands international ghosted in behind the Augsburg defence following a neat give-and-go with Dortmund striker Serhou Guirassy, who has now contributed to 10 goals in nine games in all competitions this season.
Augsburg took advantage midway through the first half when Alexis Claude-Maurice collected a loose ball and beat Gregor Kobel with a low strike from 25 yards.
Dortmund’s defensive fragility was exposed again shortly after half-time when Emre Can’s poor clearance fell to Claude-Maurice, who found the far bottom corner with a curling effort.
Dortmund cranked up the pressure in the final stages, but their afternoon was summed up when 18-year-old debutant Almugera Kabar was shown a second yellow card deep into injury time.
Sahin’s Dortmund side are still yet to win away from home in the Bundesliga this season and have taken just 13 points from their opening eight league games.
Defeat sees Dortmund drop to eighth in the table and seven points behind league leaders RB Leipzig, while Augsburg climbed to 11th after beating BVB for the first time in four years.
