Bayern suffered the law of Werder this Sunday as part of the 18th round of the Bundesliga.
The Brémois made the difference with a cannon shot from Weiser just before the hour mark (0-1, 59e).
A real setback for the Munich team, who remain seven points behind leader Leverkusen, with a match in hand which they will make up for in three days against Union Berlin.
Werder, for its part, has achieved significant success in terms of maintaining its position, now with a nine-point margin ahead of the first relegation zone.
