However, United only stay top of the league just four points clear of second place Reading after their 1-0 win at Norwich City.
Ironically the Blades travel to the Madejski Stadium next Saturday, but not before they face Plymouth on Tuesday and the Royals face Southampton at the St. Mary's Stadium on Wednesday.
To the game and United went in two goals ahead at half-time and looked good to double their lead by full-time but over estimated Derby's fire power as they attempted a brave fight back.
A bizarre incident just six minutes in opened the scoring for the home side, Sheffield United had won a corner in front of the Kop. DAVID UNSWORTH swung in a defying cross which flew past the on looking Inigo Idiakez and keeper Lee Camp before landing in the back of the net.
The goal brought back happy memories for older United fans who remembers Alan Woodward who did not take difficulty if netting from taking corners.
After this brief setback County never recovered and allowed United to play the best half of football that had been so far this season. And, as a result Neil Warnock's team doubled their lead from another corner.
Unsworth again whipped in a fierce corner to the far post which fell to Neil Shipperley who headed back into the box and after a goal mouth scrabble the ball fell kindly to PAUL IFILL who smashed the ball home.
At half-time it was an inspired substitution that turned the game on its head, former Blade PAUL PESCHISOLIDO took to the field in place of Stern John. He replayed his club by stabbing the ball home just six minutes after the break.
After that the Rams put the Blades to the wire and had the majority of the possesion whilst Mounir El Hamdaoui and Seth Johnson both came close to leveling.
It might have been old lady luck or a tower of strength that kept United in the game but never the less it did not stop the visitors from trying to temp fate which helped United come from 2-0 down to beat Watford 3-2 last week.
Nether the less the Blades eventually claimed all three points and won there seventh straight victory this season.
As we suggested in our 'Match Preview' Derby came at United with one lone striker upfront, that being in the shape of Stern John who has represented Birmingham City, Coventry City and Nottingham Forest over the last few years.
:: KICK-OFF ::
Early dominance by United paid off as little as the sixth minute, the Blades had won a corner after Paul Ifill jinxed on the wing. Unsworth delved in a low cute ball which comically evaded the Derby defence to flash straight into the goal.
The sun was shining bright on the Kop for which Spanish Midfielder Idiakez and keeper Camp claimed had blinded their view but United where 1-0 up no matter what there excuse was.
United still showed dominance and did not sit back on there lead like they would have done last season, Chris Morgan and striker Steven Kabba forced Lee Camp into action with their efforts whilst on 37 minutes the home side capitalised on lack luster defending to double the lead.
A ball floated in by Ifill was met by Shipperley who would have scored had it not being a World-Class save from Camp who palmed the ball for a corner. From the resulting corner Unsworth found Shipperley on the back stick and after a scrabble in the box Ifill shot United to a cosy lead.
:: HALF-TIME: SHEFFIELD UNITED 2-0 DERBY COUNTY ::
At half-time Stern John and Adam Bolder were spared to make way for Peschisolido and El Hamdaoui and reformed to a more traditional 4-4-2 formation.
This seemed to work as County looked to get back into the game, after Tommy Smith had fed Peter Whittingham on the left flank his loan cross fell to Peschisolido who beat his marked and then stabbed to beat Kenny at his near post for 2-1.
El Hamdaouri forced Kenny into a save while former Leeds United Midfielder Seth Johnson came very close to tying the game.
A long ball which fell near the box forced Kenny to launch out and attack the ball, he chest down before volleying over the half-way line. The ball fell to Johnson who, from 50 yards attempted to lob the ball into the empty goal, however he aimed too high which fell into the crowd in the Kop as Kenny looked unable to get back in time.
County, attempting to force a point left holes at the back and debutant Vicent de Paul Pericard should have ended the game close to the finish. Alan Quinn pounded through the middle and put Pericard through who was free on goal, he stopped and smashed the ball at Camp who somehow saved for a corner.
Despite ruling this unique opportunity to win the game early the Blades hung on and came a step further to realising their dream of Premiership Football.
:: FULL-TIME: SHEFFIELD UNITED 2-1 DERBY COUNTY ::
Man of the Match: David Unsworth