United's under 23s recorded a second straight win and extended their unbeaten run this season to four games with another four-goal haul at Colchester United.
Building on last weekend's 4-0 win at Bramall Lane against Bristol City, the Blades left it later this time around but in the end ran out comfortable winners, showing their ruthlessness in front of goal.
The breakthrough came from a set-piece. Angelo Cappello's deadly cross from the right got the lightest of touches from Iliman Ndiaye to open the scoring, but it was all that was needed to send the ball inside the far post.
The hosts hit back though just before the half hour mark, a swift counter attack undoing the Blades to ensure it was 1-1 going into the break.
It remained that way until 15 minutes from time when Paul Heckingbottom's substitutes took hold of the game.
First, Zak Brunt finished off a sweeping move, running onto Ndiaye's pass across the box after Harrison Neal had played him in.
Then as the game made its way towards a finale, Ryan Viggars fired home an emphatic finish after a poor ball out from the Colchester goalkeeper.
The Blades weren't done there either. In stoppage time, Femi Seriki added a fourth after more good work from Ndiaye down the right, leaving United's number 10 with a goal and two assists on a good afternoon for the team.
Blades: Amissah, Seriki, Cappello, Gordon, Lopata, Belehouan, Broadbent, Neal, Hackford (Viggars 65), Ndiaye, Maguire (Brunt 65).
Unused: Hiddleston, To. Williams.