United enjoyed a Boxing Day to remember at Bramall Lane, as Frank Lampard's Derby County were beaten.
Billy Sharp opened the scoring in the first-half, before David McGoldrick and substitute Leon Clarke got on the scoresheet after Harry Wilson had briefly restored parity in front of a crowd close to 29,000.
Wilder named an unchanged team for the Boxing Day encounter against the Rams, with the same 18 who were on duty at Ipswich keeping their shirts.
United were quickly out of the traps and had an effort inside 60 seconds, Egan's header clearance was controlled by McGoldrick and with Carson out of position and scrambling across his goal he curled an effort inches wide and on ten minutes, United fashioned an even better opening. Stevens header across goal from a cross field pass found Sharp, but Carson was at his best to deny the Blades skipper.
As the half hour approached, Wilson was the first player to be booked for cynically halting Basham's marauding run. But the Liverpool loanee almost opened the scoring when he shot having gone past Henderson from Huddlestone's through ball, only for Baldock to save the day. Stevens was then cautioned for catching Mount.
On 41 minutes though, it was United who took the lead, space was crafted for O'Connell to cross on the left and SHARP managed to direct a header into the bottom corner past the dive of Carson. As two minutes of added time were signalled, Duffy was booked for a foul on the advancing Wilson, but from the resulting free-kick, Mount's effort sailed harmlessly wide of the target.
The Blades made a bright start to the second period, but Bryson got back to clear as Sharp and McGoldrick looked to get an effort away from Baldock's cross. United then had strong appeals for a penalty turned down by referee Eltringham, as McGoldrick looked to pounce on a mistake by Tomori, having seen his first attempt saved by Carson.
And to rub salt into the wounds, Derby equalised minutes later. O'Connell handled as Marriott looked for a way past and WILSON fired home from the resulting free-kick, giving Henderson no chance. The Blades could have hit back, but Stevens opted to pass instead of shoot and Norwood fired over in the second phase.
As tempers threatened to boil over, the Blades regained the advantage. MCGOLDRICK got the wrong side of Tomori again and this time the defender couldn't get close enough to imped him as he lifted the ball over Carson and into the empty net.
With 18 minutes remaining, Sharp almost acrobatically added a third, but his volley on the turn was straight at a thankful Carson. And the skipper came even closely from a Stevens cross, heading inches wide with Carson beaten again. Clarke was introduced immediately afterwards, taking the place of Duffy.
But the Blades did get a third with six minutes remaining. Fleck's free-kick was headed across goal by Egan and CLARKE headed home to the delight of the Kop, with a helping hand from Bogle. Six minutes of added time were signalled, but they passed without too much fuss, as the Blades deservedly returned to winning ways.
Blades: Henderson, Baldock, Stevens, Fleck, O'Connell, Basham, Sharp, Egan, Norwood, McGoldrick, Duffy (Clarke 80).
Unused: Coutts, Stearman, Johnson, Moore, Cranie, Washington.
Derby: Carson, Wisdom (Waghorn 85), Bryson, Tomori, Keogh, Wilson, Mount, Jozefzoon (Nugent 70), Marriott, Bogle, Huddlestone (Evans 70).
Unused: Pearce, Roos, Holmes, Bird.