Union Berlin have cut Bayern Munich's lead on top of the table to three points after a come-from-behind 2-1 win at Bremen on Wednesday.
Werder, who were thrashed 7-1 by Cologne on Saturday, scored after 13 minutes through Amos Pieper but the defender turned villan just four minutes later when his poor back pass found Kevin Behrens, who found Janik Haberer for the equaliser.
Union thought they had the lead minutes later, but Sheraldo Becker's strike was ruled out for a handball by Behrens in the build-up.
Behrens was involved again in the first minute of the second half, heading in a corner while unmarked to give Union a valuable lead in their quest for a first ever Champions League berth.
Union took advantage of a 1-1 draw between Freiburg and Eintracht Frankfurt, both of whom could have joined the Berliners in equal second with a win.
Frankfurt's France striker Randal Kolo Muani scored just before halftime for a 1-0 lead, but Freiburg local boy Matthias Ginter equalised for the home side two minutes after halftime.
Also on Wednesday night, Bayer Leverkusen won their fifth-straight Bundesliga game, beating Bochum at home ahead of Sunday's blockbuster clash against Dortmund.
Leverkusen took the lead early through an eighth-minute penalty to Edmond Tapsoba. A second-half goal by Czech striker Adam Hlozek, set up by teenage midfielder Florian Wirtz on his return to the starting XI from an ACL tear, saw the home side claim all three points.
