The pressure has mounted on Borussia Dortmund boss Peter Bosz after the Black and Yellows threw away a 4-0 Revierderby lead.
Dortmund have endured a miserable run of form and that spell hit another chink on Saturday against their bitter foes.
Leading 4-0 at half time, Schalke stemmed the bleeding after the break to storm back into the contest.
Dortmund hitman Pierre-Emerick Aubameyang received a second yellow card and was dismissed and the Royal Blues crept back into the game.
Brazilian defender Naldo netted a towering header right at the death to seal the comeback, a goal that will go down in derby folklore.