United recorded a third consecutive stalemate, this time in the South Yorkshire derby with Doncaster Rovers.
Both sides had to chances at Bramall Lane and Blades goalkeeper Mark Howard had to make a double save as early as the second minute.
The draw maintains United's unbeaten record but means the Blades have not beat Doncaster in six meetings.
Manager Wilson made two changes from the weekend team, bringing in Cresswell for his first start and Doncaster-born Williams - Westlake and Cofie dropped to the bench, where they were joined the fit-again Porter. How the changes would fit into the formation was made clear soon after kick-off with United continuing with a 4-4-2 system. The back four remained unchanged, but in the midfield Williams was on the left, Gallagher on the right and McAllister slotted alongside McDonald in the centre. Further forward, Cresswell partnered Blackman for the first time.
The fixture was little more than a minute old when Howard was forced into a fine double save, first from Woods and then from Brown. Soon after Brown charged down a kick from the Blades goalkeeper, but, fortunately, the ball flew into the Kop.
For United, Cresswell fired over after five minutes following a marauding run out of defence by Maguire and a left-foot curler from McMahon needed to be tipped over the crossbar by Rovers goalkeeper Woods.
As the game reached the half hour mark neither side could lay serious claim to being on top but there were chances for both teams. Woods clawed out the ball as Blackman looked to connect with a corner, whilst Gallagher attemped an audacious 40-yarder after a poor kick by the visiting goalkeeper. For Rovers, Cotterill powered through the midfield but shot wide and a Keegan free-kick was blocked.
The opportunities dried up a little as the interval approached, both sides were still battling for supremacy, and as the players emerged for the second half there was everything to play for.
Early chances after the break went United's way. Cresswell and Blackman combined with the latter moving the ball onto his favoured left-foot but he was crowded out as he attempted a shot, whilst on 57 minutes Gallagher's free-kick from an acute angle was well held by Woods.
Both sides mades substitutes, Kitson replacing Cresswell for the Blades, and the new striker soon won a free-kick, from which Blackman fired over - the same player then went close again on 78 minutes. From Gallagher's right-wing delivery, Kitson challenged Woods and the ball broke for Blackman, 12 yards out, but he could not direct his effort towards goal.
As the encounter entered the final ten minutes United were gradually getting on top, winning a couple of corners and looking a threat aerially, whilst it appeared that Doncaster had already settled for a share of the spoils. Cofie was introduced late on and Williams was booked for pulling down Woods.
Three minutes of added time produced little of note, apart from a McAllister shot, with his unfavoured left boot, which flew wide.
Blades: Howard, Maguire, Hill, Blackman, McDonald, Collins, McAllister, Cresswell (Kitson 66), Gallagher (Cofie 87), McMahon, Williams.
Unused: Westlake, Porter, Miller, Chapell, Long.
Rovers: G. Woods, Quinn, Jones, Syers (Harper 66), M. Woods, Brown, Cotterill (Husband 86), Spurr, McCombe, Bennett (Blake 88), Keegan.
Unused: Martis, Maxted, Hume.