United's impressive home form continued with another deserved home win.
The decisive goals came in the first half with vice-captain Paul Coutts and captain Billy Sharp on target.
United made two changes to the starting XI. Coutts was available again following suspension and replaced Lundstram, who dropped to the bench. Baldock was deemed fit again and was a straight swap for the injured Freeman.
Kicking towards the Kop in the first half, the Blades were the first to register a chance after Clarke forced a free-kick out of Bacuna but O'Connell headed Duffy's set-piece wide. From the first Reading attack, O'Connell was on defensive duty, deflecting Barrow's effort wide.
The busy O'Connell was involved with a back-post header from United's first corner on 12 minutes and Reading attempted to counter in response but this time Baldock was on defensive duty.
United, though, were getting on top and went close when Fleck and Stevens linked up on the left but Clarke swept the ball just wide at the near post. The opening goal, however, soon arrived, a result of Coutts winning possession from Aluko. Baldock and Duffy then combined down the right and after Clarke was shown away from goal, the ball dropped perfectly for COUTTS to curl into the top corner from outside the penalty area.
The next chance saw the Blades go close to a second from one of the experimental free-kick moves off the training ground, but after Coutts linked up with Basham, O'Connell's shot was blocked by Gunter.
United remained on top and controlled the first half possession and territory, leading to the second goal, on 37 minutes. Baldock's reverse pass split the Reading defence and allowed Duffy the space to pass across goal for the unmarked SHARP to slot home from close range.
Reading won a couple of corners close to the break and Beerens fired in a 30-yard shot that was just wide but those moments could not prevent the United players receiving an ovation from the Bramall Lane crowd at the interval.
The start to the second period was low-key but the Blades remained on top. On 54 minutes a Duffy free-kick saw Sharp head towards goal but Mannone made a fantastic save and the rebound saw O'Connell crowded out. Soon after, another Duffy free-kick saw Coutts recycle possession and Sharp and Basham went close to converting at the back post.
Ilori fired wide, Gunter's effort was blocked and substitute McShane added himself to an attack but headed wide as Reading attempted a fight-back. Brooks replaced Duffy and Lundstram took over from Sharp.
Reading gave themselves hope with five minutes to go, BEERENS converting Barrow's pass from close range and that prompted a bit of urgency from the visitors. Basham held firm to halt a Swift run and O'Connell cut out Barrow cross.
Five minutes of added time being announced was a bonus for Reading and the additional period was entertaining.
Lundstram put Clarke through as the visitors committed bodies forward but Mannone saved with his legs. Carter-Vickers was then called upon to make two clearing headers before the final chance saw Clarke attempt to put Brooks through, although he was crowded out. No matter, the final whistle followed seconds later.
Blades: Blackman, Baldock, Stevens, Fleck, O'Connell, Basham, Clarke, Sharp (Lundstram 81), Coutts, Carter-Vickers, Duffy (Brooks 73).
Unused: Moore, Donaldson, Wright, Lafferty, Carruthers.
Reading: Mannone, Gunter, Van Den Berg, Moore, Beerens, Aluko (Swift 66), Edwards, Barrow, Bacuna (Clement 77), Ilori, Blackett (McShane 55).
Unused: Jaakkola, Kelly, Richards, Smith