United, after being afforded a guard of honour welcome from the Bantams before kick-off, blew the visitors away inside the opening quarter with two goals.
Leon Clarke netted the first, guiding the ball into the net with his left foot from 15 yards and an incisive move that included a typically barn-storming run from Jack O’Connell.
The hosts doubled their advantage in the 20th minute, Sharp applying the finish after being threaded through by John Fleck.
City’s best chance came when Mark Marshall’s floated cross found Charlie Wyke but he headed wastefully wide from inside the six yard box.
Stuart McCall made a tactical switch by withdrawing Timothee Dieng and bringing on another striker in Alex Jones. For a time, Bradford improved but any hopes of a comeback were extinguished three minutes before the interval when Clarke fired in his second goal of the afternoon.