An early goal condemned United to defeat at Queen's Park Rangers.
An unfortunate fall by goalkeeper Jamal Blackman, which resulted in him being stretchered off, was the decisive moment of the game.
Boss Wilder freshened his starting XI for the capital trip. Fleck was suspended after picking up five bookings, whilst Sharp and Duffy dropped to the bench. Into the side came Lundstram, Brooks and Donaldson, with Stearman and Hanson returning to the bench.
On Halloween, United's start couldn't have been much worse - inside five minutes, Rangers were gifted the lead. A routine through ball saw Blackman collect in the air but he collided with Carter-Vickers on his descent and dropped the ball at the feet of SYLLA to place into the empty net. Furthermore, the loan goalkeeper needed five minutes of treatment before being stretchered from the field, with Moore taking over.
United had a great chance to level when an unmarked O'Connell sidefooted a Coutts corner over the crossbar on 13 minutes, but the better start certainly belonged to the home side.
Sylla hit a 30-yard left-footer which Moore retreated to save, holding the ball just clear of the goal-line and then Freeman cut inside Baldock but fluffed his shot. Washington was also off target on 22 minutes.
Just after the half hour there was a spate of opportunities, Sylla and Washington were both off target and in between those efforts Brooks curled a cross around the back of the QPR defence but Clarke lifted the ball just over at the back post.
The final chance of the half, deep into six minutes of added time, saw Stevens get to the byline and pull back a cross but Smithies smothered Clarke's near post effort.
Early in the second half Basham pushed on with a couple of probing runs and Brooks half-volleyed over. Sylla went close with a header from a free-kick for the home side.
Sharp was introduced and had a chance inside two minutes, but Smithies saved. There was then more worries for United when, with just one substitute left, both Brooks and Baldock needed treatment. Brooks continued but Duffy replaced Baldock on the hour, prompting a change in system.
Luongo curled wide for the home side but, despite having to overcome a number of hurdles, the Blades were still in the encounter. Baptiste was forced to head away Basham's cross and Sharp was adjudged offside on 72 minutes as he provided the cross for Clarke, who headed home, but the free-kick had already been given.
Mackie fired over after Freeman got around the back of the Blades defence and in respect of United's danger, the home side slowed play down at every opportunity late on.
The Blades struggled to create chances, despite working hard. Scowen was booked for a foul on Brooks and then stayed down as if he'd been hit by a heavyweight boxer after being caught by United's diminutive midfielder. All in all it wasted valuable time and Rangers held on for the points.
QPR: Smithies, Bidwell, Freeman, Cousins (Furlong 58), Washington, Scowen, Robinson, Baptiste, Luongo, Wheeler (Manning 87), Sylla (Luongo 67).
Unused: Smith, Wszolek, Ngbakoto, Lumley.
Blades: Blackman (Moore 10), Baldock (Duffy 60), Stevens, O'Connell, Basham, Lundstram, Clarke, Donaldson (Sharp 56), Coutts, Carter-Vickers, Brooks.
Unused: Hanson, Stearman, Lafferty, Carruthers.