United completed a six-match pre-season campaign unbeaten following Friday night's victory at Doncaster Rovers.
Second half goals from David McGoldrick and Billy Sharp made it four wins and two draws to conclude preparations for the Sky Bet Championship campaign.
Moore started and he was called upon within 12 seconds to deny Coppinger - it was a sign of things to come from the Blades goalkeeper!
United's first serious opportunities saw the Doncaster goal peppered in the space of a few minutes of pressure. Freeman struck the crossbar and put the ball in the net but both times the referee's whistle had been blown, whilst Marosi was forced into saves from Lafferty and Duffy. Soon after, Lundstram's effort was deflected wide and from the resulting corner Stearman half-volleyed wide when in a good position.
Crawford linked up well with Marquis and Coppinger but couldn't find the target but the home side finished the half the stronger and the Blades had Moore to thank for keeping the scores level.
In the space of four minutes, Moore kept out efforts from Wilks a total of three times and soon after that Butler was repelled by the goalkeeper twice at set-pieces as Rovers broke quickly and also forced a number of corners.
Following half-time words from boss Wilder, the Blades looked brighter at the start of the second period and twice Clarke went close. Holmes also had an effort saved by substitute goalkeeper Lawlor after breezing through the home defence.
Clarke tested Lawlor again before a quartet of substitutions, one of which, McGoldrick, tried an acrobatic effort moments after coming on.
McGoldrick then struck the outside of a post following a move involving Freeman and Sharp but the new striker was to have more of an impact after Anderson wasted a near post header for the home side.
On 73 minutes, two substitutes combined to give United the lead. Norrington-Davies delivered a well weighted cross from the left and McGOLDRICK slid in to beat Lawlor.
McGoldrick was also involved as United hit a post soon after and then provided the assist when the lead was doubled on 79 minutes. He slid in SHARP, who let the ball drift across his body before slotting home with his left foot.
Late on both goalkeepers made saves - Moore from Rowe and Lawlor from substitute Lavery - whilst O'Connell made two blocks to protect the victory.
Blades: Moore, Freeman, Egan, Stearman (Basham 62), O'Connell, Lafferty (Norrington-Davies 62), Lundstram, Duffy (Lavery 84), Holmes (Evans 62), Clarke (McGoldrick 62), Sharp.
Unused: Henderson, Fleck, Doherty.