United gave Chesterfield a goal start before cruising to victory at the Proact.
Jon Nolan gave the home side the lead but the Blades were rampant in the second half, smashing in four without reply, with Kieron Freeman, John Fleck, Billy Sharp and Leon Clarke on target.
Done, who played 45 minutes in midweek following a fractured jaw, returned to the team for the Sky encounter. The striker took over from Scougall, who dropped to the bench after missing training this week. Chesterfield's starting XI included ex-Blades Evans and Dimaio, whilst Harry Maguire's brother, Laurence, was amongst the Spireites substitutes.
United made a terrible start and handed the lead to the visitors inside two minutes. Evans got the better of Basham and his simple pass inside allowed NOLAN to run into the box and smash above Moore's head into the net, in front of the Unitedites.
The Blades lacked the fluidity of recent weeks in the early moments but did create their first chance on eight minutes, Freeman and Sharp were involved but the ball dropped to Lafferty's right foot and he fired at goalkeeper Fulton.
Soon after Done's header was pushed around a post after United switched the play from left to right and three corners in succession kept the Spireites back, although a number of cheap free-kicks gave the home side attacking options.
Chesterfield were packing men behind the ball as United looked to get Coutts, Fleck and Duffy on the ball as much as possible. In terms of chances, Duffy's effort was on target but comfortable for Fulton, who then repositioned himself to pluck the ball out of the air from Sharp's deflected shot.
The final chance of the half, however, fell to the home side. A late O'Shea corner saw Evatt's back post header come back off the crossbar before the Blades cleared at the second attempt.
The first notable moment of the second half was referee Sarginson noting Chesterfield's timewasting on 49 minutes. Soon after, inside 60 seconds of each other, both sides had a chance but shots from Evans and Sharp were saved by Moore and Fulton respectively.
A leveller, though, was just moments away. Patient build up was rewarded when Fleck clipped in a cross from the left and FREEMAN powered in from the back post to force the ball past Fulton.
The next chance was the last before Evans was replaced. He raced down the left chance and his shot was partially blocked by Moore before Wright headed clear. For United, Lafferty headed wide a deep Basham cross and Done could not direct home Freeman's cross after a quick break.
Boss Wilder threw on Clarke for defender Wright in a positive move and it was rewarded inside five minutes. United grabbed the lead on 72 minutes when Duffy laid off to FLECK, who was afforded the space to line up a shot and beat Fulton from 20 yards.
Many of the 2,761 Blades fans inside the stadium were still celebrating when a third goal was added. Duffy was again involved, delivering a deep cross for SHARP to beat Evatt at the back post, heading past Fulton.
For the home side, Anderson headed at Moore before Wilder reverted to three central defenders but the next goal also came from the Blades, on 81 minutes. There were holes in the home defence and there were a number of passes before the ball dropped to CLARKE, who curled left footed beyond Fulton's despairing dive.
The closing minutes were a formality, United could have timewasted like Chesterfield if they wished, but opted to keep pushing forward and Lafferty had a shot deflected over before the final whistle, whilst O'Shea missed a sitter, summing up the home side's day.
Chesterfield: Fulton, Liddle, Evatt, Evans (Dennis 66), O'Neill, Dimaio, Nolan (Humphreys 69), Donohoe, Anderson, O'Shea, Ariyibi.
Unused: Mitchell, Allinson, Simons, Maguire, German.
Blades: Moore, Fleck, Basham, Sharp (Lavery 90), Done (O'Connell 78), Wright (Clarke 68), Coutts, Freeman, Ebanks-Landell, Duffy, Lafferty.
Unused: Long, Scougall, Brown, Whiteman.