Albion put in a solid showing at Old Trafford, although they did have an excellent Sam Johnstone performance to thank as they saw out the first half level.
However, drama came in the second period, when Conor Gallagher was brought down by Bruno Fernandes, leading to referee David Coote awarding a spot kick in Albion's favour.
However, despite the decision appearing correct, VAR recommended Coote check the monitor before the man in black reversed his decision, before awarding United a penalty after Darnell Furlong was deemed to have handled in the Albion box.
Fernandes saw his spot kick saved, only for VAR to intercede once again to have the kick retaken with Johnstone leaving his line before the Portuguese midfielder struck the ball.
The United man didn't make a mistake second time around, scoring from the spot to earn United all three points.
See what Albion fans had to say about the game here: