David McGoldrick's first league goal of the season will have raised Chelsea fans' fears of another home defeat to the Blades, before Tammy Abraham made it four in four against Chris Wilder's outfit to level it up.
Ben Chilwell's second Chelsea goal restored order before half-time and the hosts were rewarded for a controlled and dominate second-half display through late goals by Thiago Silva and Timo Werner.
But while Blue faces were smiling, the pain was etched all over Wilder's face as his side failed to register a single shot on goal in the second period, leaving the South Yorkshire club bottom of the table and still winless since beating the Blues 3-0 in July.
Both sides started brightly and positivity with Abraham firing wide and Chilwell forcing a save from Aaron Ramsdale early on.
But it was the Blades quick thinking that caught Chelsea cold for the opening goal. A quick short corner found Sander Berge free just inside the box, his shot as he fell headed towards goal and McGoldrick's quick and clever reaction saw him deflect the ball into the net, to be the first player to score passed Edouard Mendy in a Premier League game.
The game remained open with both keepers called into action with Ramsdale saving from Abraham and Mendy from Max Lowe from range.
So it was no surprise another goal came before 25 minutes. Mateo Kovacic made a superb run to lose his marker and get into the box, squaring into the area before the ball went out of play. Abraham unmarked scuffed his finish, hitting it into the ground, but it somehow had the accuracy to bounce over and out or reach of the Blades keeper to fall into the far corner.
The home continued their positive start and their push for a second was rewarded as they gave the visitors a taste of their own medicine.
A short corner allowed Hakim Ziyech the freedom to cross to the back post. It looked to have missed everyone, but as Ramsdale stayed on his line, when he should have come out to claim the free ball, Chilwell arrived to see the ball deflect off his hip and in.
Ramsdale atoned minutes later, diving smartly to his left to push another Chilwell effort wide
Wilder's side refused to lie-down, continuing to cause problems from set pieces, while John Lundstram stung the palms of Mendy with a fierce shot from the edge of the area just before the break.
Chelsea were controlled and calm in the second half, dictating the pace, flow and possession of the contest, not allowing their visitors one single attempt on goal.
After a host of half chances, Silva's late arrival in the box provided a free header from a Ziyech corner for goal number three to finally seal the contest on 78 minutes.
Moments later, man of the match Ziyech sprayed a 40-yard ball over the top to Werner, who lobbed over the onrushing Ramsdale only to see his effort scrap the wrong side of the right post when he should have been celebrating.
But the German was not to be denied, scoring just a minute later, racing onto a loose ball and firing home from 12 yards to seal a near perfect evening for Blues, who have only lost to Liverpool in the league this season.
Fast Results
Scores
Racecards 
