Skipper Davide Petrucci opened the scoring, before braces for Josh King and William Keane took the Reds through to a fifth round tie at Blackburn or Leyton Orient in style.
United had been quietly in control of the opening exchanges before Petrucci struck on 22 minutes. A patient, probing nine-pass move culminated in King's shot being blocked, but the Italian was the first to react to the loose ball and he expertly sidefooted a low finish around a cluster of players and just inside the post.
The coolness of his finish was matched by King six minutes later. Larnell Cole profited from defensive hesitancy from the hosts by nicking the ball just outside the six yard box, before drifting to the byline and pulling the ball back to King on the corner of the area. Although Burnley were slow to apply pressure, the