A brace from skipper Wayne Rooney helped United beat the relegation threatened Mackems after former Red Wes Brown was sent off in bizarre circumstances at Old Trafford.
Rooney scored our opening goal from the penalty spot after a foul on Radamel Falcao for which Brown was dismissed and not John O'Shea, despite protests from the visitors.
The victory strengthened United's grip on a top four place and moved us back up to third with an 11th home win out of 14 in the top flight so far this season, although Arsenal moved back above us with their 2-0 win on Sunday.
The Reds dominated possession and were initially frustrated by the massed ranks of the visitors, who went close early on when David de Gea saved well from Connor Wickham.
United almost gave the home fans the goal their start deserved when Ashley Young's shot across goal ricocheted off O'Shea onto the crossbar and Ander Herrera headed the rebound wide.
Marcos Rojo's effort from a corner was cleared off the line by Sebastian Larsson but, despite having 71% possession in the first half, United could not find a way through.
The again ineffective Angel Di Maria was hauled off at half-time and his replacement, the lively Adnan Januzaj, instantly raised the tempo and urgency of United's play.
He flashed an effort wide but Sunderland remained a threat on the counter, and from one such break away, Jermaine Defoe's half chance was smartly blocked by Jonny Evans.
The penalty incident saw Brown sent off and gave Rooney the chance to put United ahead, and he duly did so to take his goal tally for the season into double figures.
From then on, there was no way back for a Sunderland side short on goals and confidence and it was only a matter of time before United made the game safe with the second six minutes from time.
Januzaj almost capped his impressive performance with a goal, but when Costel Pantilimon parried his effort, the ball dropped for Rooney who headed in from close range to make the game safe.
Herrera had a late third chalked off after he strayed narrowly offside but this was a game that United had the better of from the first minute as we picked up a vital three points in the race for the Champions League.
United Faithful Man of the Match: Wayne Rooney
Overall team performance: 8/10
Below: A selection of pictures live from OT taken during the Reds 2-0 win!