Striker Luciano Becchio scored a stunning winner as Leeds added to Middlesbrough's problems with victory at the Riverside.
Davide Somma opened the scoring for the visitors with a low left-footed shot into the bottom corner.
Kris Boyd nipped in front of Richard Naylor to prod the leveller from Matthew Bates' inviting cross.
But Becchio lashed home a fine volley from Bradley Johnson's cutback to secure all three points for Leeds.
Boro fans greeted the final whistle with a crescendo of boos after a defeat which leaves them in 20th place, just one point above the Championship relegation zone.
Leeds, meanwhile, have risen to ninth in the table after a well-deserved victory in manager Simon Grayson's 100th match in charge.
Leeds dominated the game's opening and took a deserved lead when Somma diverted Sanchez Watt's deflected cross past Jason Steele.
Somma ought to have played in Becchio when they found themselves in a two-on-one position just before the break, but the striker chose to shoot despite his colleague being unmarked on the edge of the box.
Boro improved after the interval, drawing level after 53 minutes through Boyd.
But conceding a goal seemed to stir Leeds, who restored their advantage 10 minutes later through Becchio's superb strike, which cannoned in off a post.
The Argentine struck the bar with another shot and Leeds withstood a late Boro rally to secure victory.
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