McBurnie thought he had put the Blades ahead at Bramall Lane, as he finished off Oli Norwood’s superb free-kick from the right touchline in the second half.
But a mandatory VAR check saw the goal ruled out – because defender John Egan was offside.
Egan didn’t appear to touch the ball as it was floated in from the right, but the goal was disallowed.
VAR is being used for the first time in the Premier League this season, for match defining incidents – like goals, penalties, red cards and cases of mistaken identity.
All of United’s Premier League goals so far have been checked by VAR, but this is the first time one has been ruled out.