Borussia Dortmund's Bundesliga title hopes were dealt a huge blow on Saturday after a red card for Marco Reus and a Daniel Caligiuri double saw them lose 4-2 to Schalke in the Ruhr derby.
Reus was the first of two Dortmund players to be sent off in five second-half minutes as Schalke came from behind to hand Bayern Munich a golden opportunity to win their seventh straight league title.
League leaders Bayern can now pull four points clear at the top with three games to go with a win at relegation-threatened Nuremberg on Sunday.
Dortmund took the lead in style on 14 minutes, Jadon Sancho setting up Mario Goetze with a splendid chip over Schalke's back line.
However Schalke drew level just two minutes later, Daniel Caligiuri converting a contested penalty after a handball decision against Julian Weigl.
Two minutes later the visitors sent the Signal-Iduna-Park into shock as Salif Sane rose at a corner to put Schalke ahead.
Double disaster struck for Dortmund on the hour mark when captain Marco Reus was sent off for a studs-up challenge on Suat Serdar and Caligiuri curled the resulting free-kick into the top corner.
Marius Wolf then became the second Dortmund player to be sent off, once again for a reckless challenge on Serdar.
Axel Witsel pulled one back for Dortmund on with five minutes remaining, but their hopes were crushed a moment later when Breel Embolo fired in Schalke's fourth.
Elsewhere, RB Leipzig secured Champions League qualification with a 2-1 win over Freiburg, while fourth-place Eintracht Frankfurt were held to a 0-0 draw by Hertha Berlin.
Werder Bremen's hopes of qualifying for Europe were dealt a blow as they lost 4-1 at Fortuna Duesseldorf.
At the other end of the table, Henrik Weydandt fired bottom club Hanover to a 1-0 win over Mainz that means they still have escape relegation.