The Poland striker found the net but also received his marching orders in an enthralling encounter, won by the visitors thanks to two goals from Rudnevs
Borussia Dortmund's flagging hopes of winning a third-successive Bundesliga title suffered a devastating blow in front of their own fans, as the club succumbed to a 3-1 defeat to Hamburg.
Robert Lewandowski had raised hopes with an early opener, but later saw red as Artjom Rudnevs' double and two further strikes from Heung-Min Son meant BVB left empty-handed.
Defeat leaves BVB in second place after Bayer Leverkusen could only record a draw. The result, however, gives Bayern Munich the opportunity to stretch their lead at the top to 15 points when they host Schalke.
But that gives bayern a big advance on the second and for BVB winning the bundesliga will be like almost impossible