Borussia Dortmund slumped to a 2-1 defeat at Augsburg in the Bundesliga on Saturday and were left with 10 men as they suffered two defeats in five days.
Alexis Claude-Maurice struck twice for Augsburg as Dortmund lost again after Tuesday's 5-2 reverse away to Real Madrid after wasting a 2-0 lead in the Champions League.
Dortmund, Champions League finalists last season, have not won any of their four away games in the Bundesliga this season and remain in seventh place on 13 points.
RB Leipzig provisionally took over top spot on 20 points with a 3-1 home victory over Freiburg. Bayern Munich, who are in second spot on 17, are in action at VfL Bochum on Sunday.
Dortmund had the perfect start as they struck on the break with Donyell Malen slotting in for a fourth minute lead.
Augsburg got an unexpected equaliser in the 25th when Claude-Maurice broke through, found no resistance from four players and lots of space to drill in his shot from 25 metres.
The Frenchman, making his first league start for Augsburg, netted a second to complete the comeback five minutes after the restart, curling a low shot home from the edge of the box.
Dortmund had substitute Almugera Kabar sent off for a second booking on his league debut in stoppage time.
