Chris Basham was the hero as his second-half strike meant that Sheffield United snatched all three points in a 1-0 win over promotion rivals Leeds.
The defender, playing in midfield, stormed forward and connected with a Billy Sharp pass at the edge of the area to give the Blades a vital victory at this point in the season.
Leeds, backed by a strong crowd, pushed for an equaliser late on but were hampered when goalkeeper Kiko Casilla was shown a straight red for a foul outside the area.
The Whites had already lost Pontus Jansson to injury, effectively playing with ten men, and the Swede wore the gloves for the final few minutes.
They threatened late on, but Leeds had no reply and Chris Wilder’s men proved their title credentials, moving above Leeds into second.
Wilder made three changes to the side that beat Brentford last time out. Martin Cranie came into the back three with Basham moving into midfield. Sharp and David McGoldrick were also brought into lead the attack.
For Leeds, Marcelo Bielsa’s only change was the return of Jack Clarke to the bench. He replaced the on-loan Izzy Brown, who missed out through illness.
It was the hosts who had the best chance of the opening exchanges as Patrick Bamford saw a close range shot blocked. Pablo Hernandez exploiting space down the right-hand side before pulling it back to the unmarked Leeds forward.
Five minutes later, it was Leeds who again came close to taking the lead. Mateusz Klich’s floated cross in was met by Jack Harrison, but he could only hit his volley over from eight yards out.
It was Bamford who would threaten again moments later. The trio of Blades defenders had left three Leeds players unmarked at the top of the box. Klich’s lofted through ball was met by the Leeds forward and his early shot sailed high over the crossbar.
While Leeds dominated possession, the Blades did see opportunities and Oli Norwood had a great chance to grab a goal following Liam Cooper’s foul on David McGoldrick. The midfielder could only hit the result free-kick into the wall.
Wilder’s men had done their homework on Leeds goalkeeper Casilla’s playing style. Consecutive corners saw a swarm of fluorescent shirts pack the six-yard box, providing the home crowd with a bit of a scare until Jack O’Connell’s header went over.
The final act of the half saw Basham round Casilla one-on-one. However, Leeds players charged back and were there to prevent the ball finding Sharp, who had a chance from the area deflected behind minutes prior.
The Blades built on the momentum they had created at the end of the first-half and enjoyed more of the ball early in the second. George Baldock’s attempted cut back was denied by Gjanni Alioski, while another corner did little to trouble.
Tyler Roberts, who had been lively throughout, struck the post just shy of the hour mark. The move came from smart build-up play from Leeds which allowed Klich to receive the ball unmarked in the box, he found Roberts unmarked but the upright denied an opener.
The storm conditions that had been present all week in West Yorkshire played their part throughout and it could have had an impact on the opening goal.
Liam Cooper found the ball stuck between his feet when trying to dispossess Sharp. The Blades forward got the better of his man and teed up the on-rushing Basham, who slotted into the bottom corner from the edge of the area.
Leeds came agonisingly close to an equaliser as we entered the final five minutes. Substitute Jack Clarke’s low driven cross found Jansson, who could only deflect the ball inches wide.
Leeds pushed for the equaliser, Roberts and Stuart Dallas having shots blocked in the area. Then, Roberts nearly went through one-on-one, only to see the ball bounce out of his feet and into the arms of Dean Henderson.
The day went from bad to worse for Leeds when Casilla was shown a straight red for bringing down Sharp outside the area. Having used all three substitutes, Jansson stepped up and went in goal.
The result snaps a three-game winning run for Bielsa’s side and sees them drop into the play-offs. The Blades now holding a one-point advantage over today’s opponents.
It was a case of what could have been for Leeds after dominating the first half and seeing Tyler Roberts hit the post with the scores still level.
Kiko Casilla was sent off late to rub salt into the hosts' wounds, with head coach Marcelo Bielsa frustrated in a post-match press conference played out to the backdrop of a fire alarm.
"I don't want to underestimate the victory of the opponent," the Leeds boss said.
"If we analyse the game, we can't be unsatisfied but we're disappointed with the result.
"If the opinion is that we deserved to draw, I have a different opinion on it.
"What happened today has happened many times in the past games.
"To explain it again after such an important loss at home with our fans, our first half hour was very good.
"We conceded the last 10 minutes of the first half but we had less quality in the second half but we dominated and we had the feeling that we were dangerous."
"Great victory, not a great performance," Sheffield United boss Wilder said.
"I've said all along I am not going to be embarrassed about winning against the run of play a little bit. Because I think in 18 months at this football club, we've smashed some sides and not got what we've deserved.
"Half a dozen times last year, I've sat in my office thinking 'how have we not won it?' having drawn let alone lost it.
"It was a tough afternoon, a tough test for us and delighted against the run of play that we've come away with a result."
The celebrations at full-time belied Wilder's post-match comments downplaying the importance of this match in the automatic promotion race.
The Sheffield United manager repeated after that this was not a "season-defining" win but he was proud of the character epitomised by match-winner Basham.
"He's done well to be the match-winner because he was coming after 25 minutes because he was absolutely useless," Wilder said.
"I was going to do what their manager does and drag him off, but we kept him in it and I think he epitomised what a Sheffield United player is.
"He dug himself out of a hole and other players dug him out of a hole because he didn't have the greatest of halves of football.
"To come up with the winner was great for him. They're a good side, a really good side."