London - Wayne Rooney has scored twice as Manchester United beat Sunderland 2-0 on Saturday in a game notable for referee Roger East's error in sending off the wrong visiting player.
Sunderland kept the hosts at bay until the 64th minute, when East correctly adjudged that Radamel Falcao had been brought down in the area by former United defender John O'Shea.
But the referee inexplicably decided that fellow centre-back Wes Brown had made the telling foul and showed him a straight red card before Rooney clinically converted the penalty low into the bottom-left corner.
The England forward's second goal came six minutes from time when a shot by substitute Adnan Januzaj was parried by Costel Pantilimon and Rooney stooped to head in, unopposed, from six yards.
Victory sent United up to third place in the Premier League table, two points above Arsenal, having played a game more.
Rooney's goals, his 10th and 11th of the season, were particularly welcome given another sub-par performance by Louis van Gaal's side, and particularly record signing Angel di Maria.
The first half was one of frustration for United and their supporters, seeking to bounce back after defeat at Swansea City last weekend, with the hosts perhaps able to count themselves lucky not to have fallen behind.
Just six minutes had gone when Di Maria was dispossessed by Patrick van Aanholt, whose pass allowed Connor Wickham to advance from just inside the United half.
He reached the edge of the area before shooting and his low shot was well saved by United goalkeeper David de Gea.
Moments later, Rooney was caught in possession by Lee Cattermole, leading to an 18-yard Jermain Defoe shot that flew just over.
In similar fashion, Falcao lost the ball to Brown to set another Sunderland counter-attack in motion, this time ending in a Defoe shot that De Gea saved comfortably.
It was an uninspiring start from United, although Rooney threatened early, heading wide from eight yards at a Di Maria corner, and O'Shea might have been punished after tangling in the area with Falcao.
By the mid-point of the first half, a badly aimed Ashley Young corner ended with United passing the ball all the way back to their own goalkeeper, causing consternation and jeers among their supporters.
But United began to threaten, with Young controlling an Antonio Valencia cross on his chest and turning a powerful shot towards goal that was deflected onto the crossbar by O'Shea.
Rooney also had a free-kick punched over by Pantilimon and Marcos Rojo saw a scrambled attempt blocked near the line by Sebastian Larsson.
Di Maria had endured a miserable first half and it was no surprise that Van Gaal opted to replace him at the interval, with young winger Januzaj thrown on in an attempt to enliven proceedings.
Soon after the restart, Chris Smalling's driven cross was headed back by Falcao for Rojo, whose shot flashed just over and Januzaj was on hand, after Anthony Reveillere headed clear, to drive an effort high.
The penalty and red card drama naturally reduced Sunderland's ambition and hopes of taking anything home with them from their visit to Old Trafford.
Januzaj, in particular, seemed eager to take advantage of their fatigue and after twice forcing Pantilimon into action, he let fly with the shot that yielded Rooney's second goal.