Middlesbrough boss Garry Monk endured a miserable return to Elland Road as Pablo Hernandez and Ezgjan Alioski scored to claim all three points for Leeds.
Hernandez slid in to score from close range midway through the first half before Alioski struck to double their lead in the second period.
Britt Assombalonga halved the deficit from the penalty spot but Leeds held on for their first victory since October 21.
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