United's U23s suffered a loss away to Bolton Wanderers, despite a Ched Evans inspired comeback in the second half at Lancashire FA.
The Welsh striker scored after just five minutes of entering the field after recovering from ankle surgery and would set up trialist Charlie Scott for the Blades equaliser after United were 2-0 down at half time due to a Connor Hall penalty and an Adam Mitchell header.
Hall would strike the decisive goal in the final minutes, yet again from the spot, as United slipped to an undeserved defeat.
Just 10 minutes in, after a back and forth early period, the hosts would get a penalty as King was bundled over by Williams in the area and former Blade HALL stepped up and slotted past Eastwood to give Bolton an early lead.
Hallam would see an effort blocked after some good play as the Blades went in search of an equaliser. Bolton would double their lead, however, on 34 minutes as a quick free kick led to Noone floating a cross into the area for MITCHELL, who was judged to be onside despite appeals, to meet and head home from six yards for the Trotters.
A great save from Eastwood just before half-time denied the Trotters taking a three goal lead as King burst through on goal but failed to convert as United's goalkeeper saved low to his left.
After the interval the Blades came out with much more intensity as Hallam cut inside from the left and struck powerfully off the crossbar, bringing United the closest they had been to a goal so far.
United's good play in the second period would be rewarded as EVANS headed home a Mallon cross, also on his first start back since injury, from the right hand side at the back post to reduce the deficit on 65 minutes.
Moments later the scores were almost level as some very neat play on the right hand side saw Hallam with a shooting opportunity inside the area but his shot went just wide of a post.
The deserved comeback would be completed on 83 minutes as SCOTT fired home a half volley on the edge of the box after tireless work from the game-changing Evans on the right to create the chance.
However, the Blades would leave with nothing as a second penalty was awarded due to a foul from Williams on King which saw the defender pick up his second booking and subsequently a red card. HALL stepped up again to convert and give Bolton the winner against the run of play.
Blades: Eastwood, Deidrick-Roberts, Norrington-Davies, Scott, Hawkes, M. Williams, Gilmour, Mallon, Wright (Evans 60), Hallam, Smith.