Ten-man Derby County fought bravely but were denied a point in the final minute of normal time as Sheffield United secured a 1-0 victory over the Rams.
Billy Sharp scored from the spot after central defender Curtis Davies handled in the penalty area to earn the home side all three points as Derby fell to defeat.
The Rams showed a lot of fight, especially in the second half as they were reduced to 10-men as goalkeeper Kelle Roos received his marching orders for a foul on Sharp.
Derby did have chances in the first half to take the lead as former Sheffield United defender Phil Jagielka headed against the crossbar, whilst in the second half, Tom Lawrence was denied by Blades goalkeeper Robin Olsen.
And, in the final minute of added on time, Lawrence was denied by the post as Sheffield United secured all three points from the spot to end Derby’s two-game unbeaten run.
Manager Rooney named an unchanged line up from the impressive victory over Stoke City seven days previous for the clash against the Blades and it was the home side who had the better of the chances in the early part of the game.
Midfielder John Fleck saw a tame shot comfortably saved by Rams’ goalkeeper Roos, whilst two minutes later, Billy Sharp almost opened the scoring for the Blades.
A long ball over the top from George Baldock found the onrushing Sharp who had beaten the offside trap. He brought the ball down well but his shot went over the crossbar.
There was an interesting battle taking place on the right-hand side as brothers Sam and George Baldock came up against each other, whilst Jagielka remained steady at the back against his former club as Derby grew into the half.
And it was the centre half who almost gave Derby the lead midway through the first half. Louie Sibley’s corner found the head of Jagielka but his effort rebounded off the crossbar.
Tom Lawrence was quickest to react to the loose ball but his shot was well saved by Blades goalkeeper Robin Olsen.
The Blades were having the better of the possession, however, the Rams got men back behind the ball and frustrated their opponents.
And they almost took the lead before the break on two occasions as Derby County finished the half stronger of the two sides.
A cross from Lee Buchanan from the left found Lawrence on the edge of the box. His effort was blocked into the path of Baldock who shot instinctively on the volley but it went inches wide of the post.
Two minutes later, Derby again raced forward and created another opening. This time, midfielder Graeme Shinnie, who had been booked earlier in the half, took aim from 20 yards but saw his effort palmed away by Olsen.
The Rams had one final chance prior to the half time interval as skipper Tom Lawrence was fouled on the edge of the box. He picked himself up to take the set piece but fired against the wall as it remained goalless at half time.
It was a quiet opening to the second half with neither side troubling either goal, however, the Rams would be reduced to 10 men just before the hour mark as goalkeeper Roos was dismissed.
Sharp raced onto the ball over the top and was brought down on the edge of the area by Roos who had rushed out of his goal and the referee reached for his top pocket and sent the goalkeeper off.
The Rams needed to dig in and Rooney brought on Jason Knight to provide energy in midfield, whilst Sibley was sacrificed for Ryan Allsop to make his first league appearance for Derby County.
And predictably it was the Blades who were in the ascendency following Roos’ dismissal. Morgan Gibbs-White took the resulting free kick and was denied by the wall, whilst Iliman Ndiaye saw an effort blocked just after the hour mark.
The game started to become stretched, and with home supporters willing their players forward, the Rams almost profited on the counter attack.
After substitute Kamil Jozwiak did well to keep the ball in play with 68 minutes on the clock, he found Lawrence with space to shoot, which he did. He struck it sweetly from 25-yards which Olsen spilled but he gathered at the second attempt.
With Derby continuing to battle and hold their opponents at bay, their hard work was almost undone as Illiman Ndiaye had a free header from six yards, but thankfully for the Rams, he headed well wide of Allsop’s goal.
However, with Derby so close to hanging on, Sheffield United were awarded a penalty in the final minute of normal time after Davies handled in the penalty area.
Sharp stepped up and fired straight down the middle to secure all three points for Sheffield United on a cruel afternoon for the Rams.
However, with one of the last kicks of the game, Derby nearly salvaged a point as Lawrence turned excellently on the edge of the box and raced through on goal but was denied by the post as the Rams fell to defeat.
Sheffield United: Olsen, Baldock, Fleck, Sharp ©, Egan, Norwood (McBurnie 65’), Davies, Osborn, Gibbs-White, Ndiaye (Hourihane 80’), Norrington-Davies (Stevens 71’)
Substitutes: Foderingham, Basham, Brewster, Guedioura.
Derby County: Roos (GK), Byrne, Shinnie, Jagielka, Bird, Baldock (Jozwiak 65’), Lawrence (C), Morrison (Knight 58’), Sibley (Allsop 58’), Buchanan, Davies.
Substitutes: Forsyth, Stearman, Stretton, Watson.