A quick-fire hat-trick from James Beattie - his first in United's colours - ensured that a victory over the Leicester was in the bag before 20 minutes were completed at Bramall Lane.
The striker took his tally for the season, all in the Championship, to 19 and in the process netted United's first hat-trick since Paul Peschisolido's treble at Gillingham in January 2004.
Beattie's goals came after 12, 14 and 19 minutes, the first of which from the penalty spot after Patrick Kisnorbo was sent off for upending Billy Sharp. With the comfortable advantage, the Blades looked impressive in recording a league double over the Foxes.
With Morgan suspended, Kenny struggling with a back complaint and Hulse having a groin problem, boss Blackwell made a total of four changes. He brought in Bennett, Ehiogu, Quinn and Beattie, whilst youngster Law, the reserve team's leading scorer, was named amongst the substitutes.
A heavy downpour made conditions difficult early on, but the home side made a bright start and McAuley conceded the game's first corner, preventing Sharp getting on the end of Beattie's cross.
Naysmith cut out a dangerous run by Fryatt before the sun began to shine at the Lane, particularly on Beattie!
The game had just reached the ten-minute mark when the action began to hot up. Sharp chased a flicked on through ball down the left channel and fell in the box after coming together with Kisnorbo. There were appeals for a penalty and referee Pike looked over to one of his assistants, who indicated a spot-kick. The man in the middle agreed, Kisnorbo was deemed to be the last man and was dismissed before the penalty could be taken. BEATTIE's spot-kick was parried by Henderson but the ball squirmed loose and the striker forced home the rebound.
Leicester felt hard done by and Stearman took out his frustration on Sharp with a foul 25 yards from goal. The visiting defender then held his head in his hands as BEATTIE drilled home the resulting free-kick, although Henderson made a mess of an attempted save.
The Foxes attempted to regroup and won a corner but from the resulting breakaway, United added a third? and the scorer was predictable. Cotterill's run down the right caused problems and after his shot deflected off Oakley, Tonge delivered a corner for BEATTIE to head past the hapless Henderson from just six yards.
Leicester fans in the Bramall Lane end were stunned but continued vocal supporting their team, who were struggling to get out of their half. After a busy start Henderson was given a little respite midway through the half but Stearman's crude challenge on Quinn earned him a booking.
Cotterill's pace was a danger to the home side and from one of his crosses, Stearman, positioned in between Sharp and Beattie, cleared over his own crossbar.
Late on in the half the visitors worked themselves two long range efforts. Howard's left-footer was a yard wide of the right post and then Bennett was ideally placed to hold Oakley's speculative shot.
Three minutes of injury-time was added and the rain again began to fall before the half-time whistle arrived.
Within a minute of the restart Howard shot at Bennett, but United were quickly back on top, with Cotterill prominent. The on-loan winger supplied a deep cross for Quinn to pull down on his chest but the subsequent shot was rushed due to the presence of Stearman.
Cotterill was hacked down by Mattock but no penalty was awarded and Beattie volleyed over with his left-foot after Naysmith's cross.
Leicester made a double substitute and Chambers' first contribution was a risky challenge on Quinn in the penalty area. Moments later, from a breakaway, Speed and Kilgallon got in each other's way and Howard put Fryatt in the clear but Bennett raced off his line to make a fine block and the striker squandered the rebound.
Beattie was replaced at the three-quarter mark - obviously with Tuesday in mind - and received a rapturous standing ovation. United were whipping in crosses from all angles, particularly Cotterill, and the home defence were forced to work overtime to keep the scoreline down.
After Sharp twisted and turned on the right, Stead's shot was blocked by Chambers and the last few moments - plus added-time - were incidental, although Ehiogu helped out Bennett in a crowded penalty area as United returned to winning ways ahead of the Sheffield derby.
Blades: Bennett, Naysmith, Beattie (Stead 67), Cotterill (Gillespie 86), Speed, Kilgallon, Tonge (Law 89), Halls, Sharp, Quinn, Ehiogu.
Unused: Carney, Geary.
Leicester: Henderson, Kisnorbo, N'Gotty, McAuley (Worley 73), Bell, Fryatt, Wesolowski, Stearman (Chambers 64), Mattock, Oakley (King 64), Howard.
Unused: Laczko, Douglas.
