In the late game in Germany's top-flight on Sunday, Werder Bremen were then held to a goalless draw with St Pauli after having two goals disallowed, which meant they missed the chance of going level with Borussia Dortmund, who sit sixth and in the likely last European berth.
Union broke the deadlock in the 17th minute in their match on Sunday after the Bochum defence failed to properly clear a corner. The ball fell back for Benedict Hollerbach, who lashed a shot from the edge of the area, which took a deflection before hitting the bottom of the net.
But Bochum levelled in the 68th minute, Matus Bero having his spot-kick saved, but striking the rebound home.
Union defender Diego Leite had to be carried out on a stretcher after being hit by the ball on his neck, but coach Steffen Baumgart said the injury was not "as dramatic as initially seemed."
Bochum remain bottom of the table with three games left and could be relegated for a seventh time on Friday against also relegation-threatened Heidenheim.
Bochum and Union had caused a stir in the reverse fixture, the result of which is still pending in connection with the incident of a lighter being thrown.
Their game in Berlin on December 14 originally ended 1-1, but the German Football Federation (DFB) declared Bochum 2-0 winners in two rulings because their goalkeeper Patrick Drewes was hit by a lighter thrown from the Union end shortly before the end.
The match was interrupted for around half an hour and then completed without Drewes, with an outfield player having to take his place because Bochum had made all their substitutions.
Union have contested the final DFB ruling and brought the case before an independent arbitration panel which said it would announce its ruling before the end of the season.
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