Albion won their first game at Bramall Lane for 14 years to move within four points of leaders Norwich.
Here's our player ratings:
Sam Johnstone: Could do little with United's opener and was basically a passenger in the second half after Albion took over. 6/10
Tosin Adarabioyo: Was overrun in the first half as Utd attacked down his flank. Looked far more assured after Albion's tactical switch provided him with cover. 6/10
Craig Dawson: Will be disappointed not to have stopped the first but started Albion's second with an exquisite outside of the boot pass into midfield. 7/10
Ahmed Hegazi: At fault positionally for the goal but then was immense heading everything away. 7/10
Kieran Gibbs: Another who looked a bit overwhelmed early on but made up for it after the break. United couldn't handle his overloads and then smashed home Albion's winner. 8/10
Gareth Barry: Absolutely immense in Albion's midfield. One of the best performances in a striped shirt in recent years. Capped off with a goal that inspired Albion's comeback. 10/10
Matt Phillips: Absent much of the first half and struggled to get into the game but came to life when his persistance set up Albion's second. 6/10
Jake Livermore: Another who grew into the game after the host's fast start. Was overshadowed by Barry in midfield - but then so was everybody else. 6/10
Harvey Barnes: The song is true. He will tear you apart. Set up Albion's first and second and probably should've scored when set free. 8/10
Dwight Gayle: Didn't seem comfortable out on the right and was unfortunate to be hauled down when through on goal. Did the hard yards late on to protect Albion's lead. 6/10
Jay Rodriguez: One of those nights for J-Rod when everything he tried seemed to fail. Can't question his levels of effort or commitment though. 6/10.
Chris Brunt: Came on late for Barnes to help over the line. Didn't get a great reception from the Blades but was treated to a chorus of Happy Birthday after the final whistle from the travelling fans. 5/10.