Pascal Struijk and Mateo Joseph struck second-half goals to secure Leeds a 2-0 Yorkshire derby win and consign Sheffield United to their first defeat of the season.
Leeds skipper Struijk scored the first league goal conceded by the Blades in seven matches and substitute Joseph added a late second.
Daniel Farke's side leap-frogged the visitors in the Sky Bet Championship table and extended their unbeaten league run to five matches.
Leeds now sit third behind Sunderland and Burnley, with Sheffield United fourth, despite the Blades dealing with a two-point deduction after defaulting on payments to other clubs during the 2022/23 season.
Blades boss Chris Wilder has quickly reinvigorated the South Yorkshire club following their miserable 2023/24 season in the Premier League and they looked on course to frustrate their hosts and eke out a vital point.
But Struijk's goal gave Leeds a deserved lead on the balance of play at Elland Road, while Joseph's effort was only the fifth league goal the visitors have conceded this season.
Tributes were paid before kick-off to former Blades defender George Baldock, who died at his home in Greece last week aged 31.
A minute's silence was spontaneously turned into a minute's applause by both home and away fans, while the players wore black armbands.
Leeds began to find their rhythm midway through the first half and Largie Ramazani twice threatened to give the home side what would have been a deserved lead.
The forward struck the outside of a post from a tight angle and then forced Blades goalkeeper Michael Cooper into a brilliant low save.
Brenden Aaronson, who was in action for the USA on Wednesday, pulled his effort off target and Willy Gnonto was crowded out when inadvertently played in by Blades striker Kieffer Moore.
Aaronson then volleyed Junior Firpo's cross over the bar as Leeds finished the first half on top, but the Blades held firm.
Former Leeds captain Lucas Radebe was given a rapturous reception when introduced as a special guest during the interval and the ex-South Africa defender will have been impressed by the visitors' organisation and resolve.
Leeds continued to probe after the restart but the Blades' rearguard still refused to budge.
Scoring chances remained a rarity and Aaronson blazed another effort over the crossbar before Firpo mis-cued in the box.
The Blades briefly threatened after Joe Rodon's mis-placed pass but the Leeds defender recovered to block Harrison Burrows' shot and Ollie Arblaster's stinging drive deflected off Ao Tanaka for a corner.
Leeds then broke the deadlock, becoming the first side to score a league goal against the Blades since August 24.
Rothwell swung over a corner from the left and Struijk was first to the ball, sweeping a first-time left-footed shot high into the net.
But Leeds were not yet done and in the final minute Piroe's clever pass picked out Joseph, a 79th-minute replacement for Ramazani, and the striker out-muscled the blades defence to fire home.
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