United's slender chance of reaching the play-off remain after battling goal-less draw in Saturday's South Yorkshire derby with Barnsley.
Inn a gritty performance, Che Adams came close with a shot which was pushed onto a post.
For the fifth game in a row, the Blades manager kept faith with his starting XI and personnel on show needed to be well drilled in a frantic opening 15 minutes, which saw a lot of end-to-end action, even though the only shot of note was a weak Hammill effort, straight at Long.
Goalkeeper Long saved from Hammill again soon after, following a Fletcher break down the left, ahead of a spell of Blades pressure. On 23 minutes, from an Adams cross, Sharp's challenge on Davies saw the goalkeeper drop but Done's rebound was kicked away by Roberts, then Davies made a fine save from a powerful Adams shot, turning onto a post, after good battling by Flynn.
Basham's effort was deflected over the crossbar after Roberts failed to clear a Done corner and the high-energy action continued through the half hour mark.
Barnsley had the ball in the Blades goal on 37 minutes but a whistle for a foul curtailed celebrations in the away end. Flynn, going towards his own goal, was under pressure from the visiting front two and one was adjudged to have fouled before Fletcher slotted past Long.
Fletcher was involved early in the second period too, half-volleying wide, whilst Hammond and Done picked up bookings. United's first effort after the restart came from a McEveley cross but Sharp was ushered away from Basham's header by Mawson.
Good work between Adams and Done on the left saw the latter's pull-back drop behind both Flynn and Sharp, whilst Hammill cut in from the left and let fly with a 25-yard shot, which was just a yard wide.
The closing 15 minutes remained frantic and end-to-end. For United Baptiste picked out Woolford, who almost saw laid in Sharp, whilst Fletcher headed wide a Hammill cross after Baptiste was dispossessed.
United added another striker for the latter stages and it almost worked when Sammon's shot was blocked from a Baptiste break, whilst four minutes of added time saw Sharp head at Davies from a Baptiste cross and Cuvelier have a shot blocked as Barnsley rode their luck.
The very last kick was a Sharp overhead kick, which flew a yard over the crossbar, before the final whistb>le signalled another derby stalemate.
Blades: Long, Basham, Flynn, Coutts, Sharp, Done (Woolford 82), McEveley (Sammon 88), Baptiste, Adams, Edgar, Hammond (Cuvelier 72).
Unused: Howard, Calvert-Lewin, McGahey, Whitman.
Barnsley: Davies, Roberts, Scowen, Hourihane, Winnall, Brownhill, Fletcher, Hammill, Williams, Mawson, Isgrove.
Unused: Nyatanga, McCourt, Townsend, Khan, Toney, Tuton, Chapman.