Flum gave sixth-placed Schalke the lead when he headed Atsuto Uchida's cross into his own goal in the 14th minute and Cameroon defender Joel Matip compounded his agony by adding a second goal four minutes later.
The midfielder atoned for his mistake by heading in from a Tranquilla Barnetta free kick in the 56th minute before Spaniard Joselu scored twice to put Eintracht in front by the 68th minute.
The hosts were denied a first league win since Sept. 14 when Benedikt Hoewedes fired home with four minutes left.
The afternoon games served as an appetiser for the evening's heavyweight clash between Borussia Dortmund (28 points) and leader Bayern Munich (32).
Stefan Kiessling scored his 13th goal of the season to give title-chasing Bayer Leverkusen, who started the weekend in third with 28 points, a 1-0 win at Hertha Berlin.
Two goals from Halil Altintop gave Augsburg a 2-0 win at home to Hoffenheim while Nuremberg, the only winless team in the league, held VfL Wolfsburg 1-1 at home.
A Gelson Fernandes goal gave Freiburg a 1-0 win at fellow strugglers Eintracht Braunschweig.
- Sports & Recreation
- Atsuto Uchida
- Borussia Dortmund