The England striker netted his opener from the penalty spot and completed his brace following Wes Brown's wrongful dismissal, though the Argentine's woes continued
Roger East awarded a penalty after John O’Shea fouled Radamel Falcao in the box – leading to Rooney’s opener – but the official then showed Wes Brown the red card, despite O’Shea’s protestations.
|VIEW FROM OLD TRAFFORD
|By Pete O'Rourke
Manchester United got back to winning ways to boost their top four hopes, but it was again far from convincing.
Sunderland frustrated United for over an hour before the game turned on the penalty awarded for a foul on Radamel Falcao. John O'Shea appeared to bring Falcao down inside the box but, much to the defender's bemusement, referee Roger East decided to send off Brown for the incident instead.
Wayne Rooney scored from the spot before adding another late on as United took control against the 10 men. It may not have been pretty and for long periods United flattered to deceive, but all Louis van Gaal will be concerned about is the three points that lifted United back up to third spot in the table.
Rooney headed a corner wide at the near post in the fourth minute as United made an encouraging start, although Sunderland soon fired two early warnings of their own.
Connor Wickham, one of three players recalled by Gus Poyet following last week's goalless draw with West Brom, raced towards a backpeddling home defence and drew an excellent low save from David de Gea, before Jermain Defoe curled a strike narrowly over in the seventh minute.
United looked to hit back quickly, and Ashley Young drove a shot over the crossbar when Lee Cattermole partially cleared, before Defoe failed to trouble De Gea with a 16th-minute chance.
An unsettled home crowd almost had something to cheer when Young hit Antonio Valencia's right-wing cross goalwards at the back post, but O'Shea slid in to divert the ball against his own crossbar.
That 25th-minute opportunity prompted an increase in tempo from United, but they were unable to find the breakthrough before half-time.
Van Gaal sent his side out early for the second period and replaced the ineffective Angel Di Maria with Adnan Januzaj.
Sunderland found themselves under intense pressure after the resumption, with Marcos Rojo lashing a shot over from Falcao’s knockdown.
Januzaj then sent a rasping 20-yard effort wide following a poor headed clearance from Anthony Reveillere, before East made an unlikely hash of a relatively straightforward penalty situation, and Rooney kept his calm to pick out the bottom corner from 12 yards.
Sunderland goalkeeper Costel Pantilimon was a busy man as United poured forward during the closing stages and, when he could only parry another firm Januzaj strike, Rooney was on hand to head home his second and ensure Sunderland's winless Premier League run extended to four matches.