The Black Cats attracted a crowd of more than 40,000 and their fans were rewarded with second-half goals from David Connolly and Grant Leadbitter that finally ended the gritty performance of the visitors.
And as the tempo increased in the later stages, Leeds assistant manager Gus Poyet was sent to the stands by referee Graham Salisbury following a petty incident involving two balls on the pitch at the same time.
Leeds, without leading goalscorers David Healy and Robbie Blake, were unable to make much impression on a reshuffled Black Cats defence, although Ugo Ehiogu was just off target with a close-range header from a Jonathon Douglas corner.
Leadbitter tried his luck from all of 30 yards with a thundering drive that was fumbled by goalkeeper Tony Warner and scrambled behind for a fruitless corner.
The recalled Lewin Nyatanga released Liam Miller whose low centre flashed across the face of goal where Warner just beat the lurking Connolly to the ball.
The Black Cats continued to press forward with the lively Stephen Elliott linking up with Dwight Yorke and Miller for the latter to have a low drive deflected behind.
And in the 38th minute only a brilliant save by Warner kept the sides on level terms. Yorke moved the ball out wide to Elliott whose powerful drive was turned behind in style by the keeper.
In a rare Leeds attack, Douglas brought in the overlapping Ian Westlake and it took a last-ditch tackle by Stanislav Varga at the expense of a corner to clear the danger.
Sunderland's attacks, however, carried more threat and a surging run on the left by Daryl Murphy had the visitors on the retreat.
Manager Roy Keane's pep talk had obviously concentrated on shooting on every opportunity with Miller and Murphy firing just off target after the interval.
And in a bid to add more attacking power, Keane hauled off Elliott and Nyatanga in favour of winger Ross Wallace and the more experienced Danny Collins.
After Warner had saved well from a Murphy flick, Sunderland surged ahead in the 65th minute. Yorke founded Connolly who turned cleverly to beat Matt Heath and fire home his fourth goal of the season.
Leeds boss Denis Wise responded by making a triple change, sending on Healy, Ian Moore and Matt Kilgallon but to no avail as the home side struck again in the 81st minute.
Murphy forced his way into the penalty area and when crowded out he found Leadbitter and the youngster beat Warner with a fierce drive.
Sunderland piled on the pressure with the overlapping Dean Whitehead and Connolly desperately unlucky not to increase the lead in the closing stages.