The forward earned and converted the spot-kick in the final few minutes of a game played in foggy conditions in the Black Country as the home side looked set to inflict a third successive defeat on the Reds.
The deadlock had been broken by a man whose surname conjures up images of United's distant past, as Daniel Meredith headed the Baggies into the lead.
The hosts carved out the first opening when Jonathan Leko combined nicely with Kyle Edwards, only to fire his shot way off target, but little else of note was created until Aidan Barlow drove through the middle, taking allcomers on, until being crowded out and going to ground inside the box.