Ole Gunnar Solskjaer’s team, outplayed for 70 minutes by the promoted side, trailed 2-0 after a first-half goal from John Fleck and a second-half effort from Lys Mousset.
Chris Wilder’s team were hungrier and more incisive but from nowhere United were back in the game, with 19-year-old Brandon Williams scoring in the 72nd minute.
Manchester United suddenly looked full of ideas and incisive running, with the game turned on its head.
Solskjaer threw on Mason Greenwood to replace Andreas Pereira, meaning they were now operating with an attacking quartet of Greenwood, Marcus Rashford, Anthony Martial and Daniel James.
Just five minutes after Williams’ strike, Greenwood equalised, finishing from close range after Rashford’s cross.
With the home side rocking badly, United poured forward again and Rashford swept home.
But the drama was still not over, with Oliver McBurnie controlling the ball and firing past David de Gea to level at 3-3. The goal stood after a VAR check.
