Neil Warnock made his latest return to Bramall Lane as Palace manager on the back of a convincing 4-2 away win in midweek to take on a Blades side who went into the match with only one defeat in their last six matches.
Two changes were made by the boss as Alan Lee and Claude Davis came into the starting eleven.
The best of the early chances saw Ched Evans have a close range shot deflected out for a corner. At the other end on 13 minutes a Jose Fonte shot was saved low down by Mark Bunn in the United goal.
The breakthrough came for the home side on 21 minutes when Stephen Quinn picked up the ball on the right hand side and his cross was converted into the net by Lee Williamson even though Davis made a last ditch effort to clear off the line.
This was a period of the game where the Blades enjoyed the majority of possession and Evans had a couple of opportunities, one blocked by Victor Moses for a corner and another saved by Julian Speroni.
Palace had a chance from distance to get back in the game with a free kick outside the box but Darren Ambrose saw his well struck set piece go just over the goal without troubling the keeper.
No further chances in the half as that Williamson effort seperated the two sides at the interval.
One change by the Palace camp at half time as Sean Scannell came on for Ambrose.
The first chance of the half came seven minutes in as a Stephen Quinn cross from the left found its way through to Evans who couldn't get his shot on target and Speroni wasn't troubled.
Just past the hour mark it was time for another change as the visitors searched for a way back in the game, Freddie Sears came on for Ertl.
In a half of few chances to either side, within a minute one came at each end. Kyle Walker shot over the bar from 18 yards out whilst Victor Moses got the better of his man inside the box but shot over the bar.
Soon after Neil Danns tried from distance but his effort went wide of Bunn's left hand post.
Latter stages of the game saw the home side pushing to extend their lead as Jamie Ward had a shot saved by Speroni whilst the keeper watched a cross-cum-shot go wide of his post from the same player with five minutes remaining.
It was not long though before the win was confirmed, with the match into added time Quinn fired the ball home from close range into the bottom corner of the net to confirm all three points for Blackwell's side.
Sheff Utd Bunn, Walker, Morgan, Kilgallon, Taylor, Ward (Camara 87), Harper, Williamson, Quinn, Evans (Stewart 80), Cresswell.
Subs Not Used: Bennett, France, Reid, Little, Kallio.
Crystal Palace Speroni, Butterfield (Clyne 55), Fonte, Davis, Hill, Ambrose (Scannell 46), Danns, Ertl (Sears 66), Derry, Moses, Lee.
Subs Not Used: Carle, Andrew, Smith, N'Diaye.
Booked: Derry, Ertl, Danns, Hill.
Att: 25,510 Referee : Colin Webster (Tyne & Wear).