A 43rd minute header from Jay Bothroyd gave Sheffield Wednesday the lead in what was a domination from the home side in the first-half.
United looked to have settled well in the opening ten minutes but a Jay Bothroyd pile driver changed the momentum in the game. Kenny was lucky to see his attempted save see the ball hit the bar but from their the Owls took control.
Antonio had a free header from a free-kick after he broke free from Jason Pearce, but the midfielder panicked and his header went over the bar.
Leeds' best chance came from a Michael Tonge free-kick which was palmed away by Kirkland.
The main talking point of the first-half was a Luciano Becchio handball that should have been seen and resulted in a red card. Instead the ref missed it and Leeds got away with it by the skin of their teeth.
Michael Brown and Becchio have felt the wrath of Llera's elbow and the Wednesday defender is lucky to be still on the pitch.
With two minutes to go, Bothroyd jumped up above everyone else to head the ball into the bottom corner and gave the Owls a deserved lead at half-time.