Bundesliga leaders Borussia Dortmund suffered their first league defeat since December as Ji Dong-won scored twice for FC Augsburg.
The South Korea winger gave the hosts the lead against his former club midway through the first half.
He doubled their lead on 67 minutes with a delicate chip over the keeper that sailed into the top right corner.
Dortmund striker Paco Alcacer scored a late consolation with less than 10 minutes to go.
The result sees Dortmund stay top of the table but Bayern Munich could draw level on points with victory over Borussia Monchengladbach on Saturday.