RB Leipzig lost 1-0 at Borussia Monchengladbach on Saturday when their on-loan player Hannes Wolf scored against them as they slipped off top spot in the Bundesliga.
It was their first league defeat of the season and snapped Leipzig's nine-game unbeaten run away from home.
Gladbach's Alassane Plea wasted several good chances after the break before Wolf, who joined this season on loan from Leipzig, fired in from a Patrick Herrmann layoff on the hour.
The hosts should have scored again but Plea rattled the bar with a powerful shot. Leipzig, who were demolished 5-0 by Manchester United in the Champions League in midweek, were toothless apart from two first half Yussuf Poulsen efforts.
The result lifted Gladbach to fourth on 11 points after six games, with Leipzig dropping to third on 13, two behind new leaders Bayern Munich and Borussia Dortmund.
"It kind of felt like a draw," said Leipzig coach Julian Nagelsmann. "Our pressure over 90 minutes was just not enough to speak of an unfortunate defeat. But it was also not a hugely deserved defeat."
Wolf spent a hapless season at Leipzig after joining from sister club Salzburg and, with only a handful of appearances last term, made more headlines off the pitch with social media posts of luxury watches, expensive restaurants and private jets.
"A weight has been lifted off my shoulders," Wolf said. "I had been waiting for such a moment for a year and a half. Such a game gives you self-confidence. I seem myself as a Gladbach player and hope to be here for longer than just a year."
