Niclas Fuellkrug scored on his return to Borussia Dortmund on Friday as Werder Bremen scored twice to snatch a dramatic late 2-2 draw against the Bundesliga leaders.
On his first visit to Dortmund since leaving the club for West Ham in 2024, Fuellkrug headed a stoppage-time equaliser in a game with all four goals in the last 10 minutes.
Dortmund dropped their first points of the season, after winning their first four games.
The draw handed Bayern Munich the chance to take top spot if they win away at Augsburg on Saturday.
Dortmund laboured in the first half against a miserly Bremen defence, with only a handful of chances at either end.
Marcel Sabitzer grazed the post with a direct free-kick, while Ludovit Reis missed a good chance for Bremen on the counter-attack.
Maximilian Beier forced a good save from Bremen keeper Karl Hein just before the break, in a moment that set the tone for a sprightlier second half.
Dortmund came out swinging after halftime, but were kept at bay by a string of brilliant saves from Hein.
Fuellkrug had a brief chance after latching on to a long ball at the other end, but Dortmund continued to dominate.
Arsenal loanee Ethan Nwaneri found the net for Dortmund with a superb overhead kick on the hour, but was denied his first Bundesliga goal by a foul in the build-up.
Daniel Svensson broke the Bremen resistance on 80 minutes, poking the ball in from close range on the counter-attack.
Schlotterbeck headed in from a corner five minutes later, but Dortmund were stunned in a rollercoaster final few minutes.
Reis smashed in a fizzing low shot from long range to give Bremen hope on 88 minutes, before Fuellkrug headed in from a free-kick in stoppage time.