David McGoldrick's 13th league goal of the season took Sheffield United back into the automatic promotion spots with a 1-0 win at play-off chasing Preston.
With the stakes high for both sides in Lancashire, McGoldrick's first-half tap-in secured all three points for Chris Wilder's side, as they leapfrogged rivals Leeds into second place.
Alex Neil's Lilywhites remain 10th in the table, five points outside of the play-off places, with six Championship games to play.
Both sides struggled to create clear-cut chances in a high-tempo start to the game, with a succession of free-kicks disrupting the flow of a match in which both sides knew the importance.
Preston's Callum Robinson had the clearest chance of the opening half-hour, taking Alan Browne's pass in his stride, but his close-range snap-shot was well saved by Dean Henderson on 17 minutes.
However, it was the visitors that broke the deadlock on 33 minutes. John Egan's towering header from Oliver Norwood's deep corner was acrobatically tipped onto the bar by Declan Rudd, and McGoldrick prodded in the rebound from a yard out.
Robinson had an excellent chance for a quick reply on 42 minutes, after great work from Sean Maguire on the left wing, but his placed finish was blocked by the retreating Enda Stevens.
Republic of Ireland international Robinson had a third chance to equalise for the hosts, just seconds after the restart, but he delayed his strike and Henderson was able to smother.
Veteran striker Billy Sharp almost extended the Blades' lead on 53 minutes after McGoldrick put him clean through with a reverse pass, but Rudd was quick off his line to make the save.
The away side defended resolutely in the second half, with Egan the standout performer as Wilder's side looked to shackle Preston's counter-attacking threat.
Egan continued to be a real handful in the opposition penalty area, thumping a header just wide on 58 minutes before forcing Rudd into save from another set-piece three minutes later.
Preston did have chances to get themselves back into the game, with Maguire skewing a header wide of the post from substitute Louis Moult's driven cross on 66 minutes.
Neil's side almost stole a point deep into added time but Moult could not keep his header down from Browne's in-swinging corner.
The final whistle went to take United back into the top two, seven points adrift of leaders Norwich.
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