Titus Bramble's own goal allowed Manchester United to tighten their stranglehold on the Premier League title with a narrow victory at Sunderland.
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The luckless defender unwittingly turned Robin van Persie's 27th-minute shot past keeper Simon Mignolet after it had also clipped Phil Bardsley on its way to goal.
It proved enough to hand United a seventh successive league victory on a day when they were far superior to their relegation-threatened hosts for long periods, but were unable to make their superiority tell.
The Black Cats were barely in the game before the break, but buoyed by United's failure to build upon their lead, rallied after it without ever testing keeper David de Gea as they extended their run without a league win to eight games in front of a crowd of 43,760.
United probably should have killed the game off long before the final whistle, but they did enough to extend their lead at the top of the table, for a few hours at least, to 18 points, the perfect preparation for Monday night's FA Cup quarter-final replay at Chelsea.
It was Nelson Mandela Day at the Stadium of Light with the club celebrating its recent collaboration with the former South Africa president's foundation at a time when the 94-year-old is battling a lung infection in hospital.
The omens for a Sunderland change of fortune were hardly promising - the had beaten United only once in 23 previous Premier League encounters - and they proved depressingly accurate before the break.
Sir Alex Ferguson did not even include Rio Ferdinand and Wayne Rooney in his 18 with Monday's trip to Stamford Bridge looming large, but his side eased their way through the first half without ever having to find top gear.
There were 12 minutes gone when full-back Alex Buttner embarked upon a determined run which took him past both Craig Gardner and Bardsley and deep into the penalty area, where Mignolet managed to block his close-range effort.
The Belgian had to be equally alert three minutes later as the Dutchman threatened to get on the end of a through-ball, and he then had to claw an Ashley Young cross out of his top corner as the visitors found their rhythm.
However, even he could do nothing about the chain of events which led to the opening goal with 27 minutes gone.
Van Persie picked up possession on the left side of the penalty area, but found himself confronted by Bardsley.
The striker patiently worked himself into a position to shoot, but when he unleashed his drive, it flew off Bardsley's boot on to Bramble's knee and inside the far post.
It was a devastating blow for the Black Cats, who had earlier seen appeals for a penalty for Rafael da Silva's challenge on Gardner waved away, and they visibly wilted as they sensed the game slipping away from them.
Van Persie forced a smart near-post save from Mignolet with a 38th-minute snapshot and then prompted him to tip over a fiercely-struck free-kick four minutes later with the points seemingly there for the taking.
Sunderland mustered only two attempts of note, both from Gardner and both off his weaker left foot, but first Nemanja Vidic and then Chris Smalling made blocks.
The home side returned knowing they had to go for broke if they were to get anything out of the game, but United retained possession at will with the movement of Shinji Kagawa and Van Persie, and Michael Carrick's composure simply too much for their hosts, who were seeing too little of the ball to bring wide men Adam Johnson and James McClean into play.
However, the former Manchester City winger finally got the bit between his teeth with 59 minutes gone when he burst into the penalty area.
His cross was blocked, but Bardsley latched on to the loose ball, only to fire harmlessly over the top.
The home side threatened once again seconds later when striker Danny Graham crossed from the right towards Stephane Sessegnon, who was only just beaten to the ball by substitute Jonny Evans.
The mood inside the Stadium of Light lifted instantly as Martin O'Neill's men belatedly forced United on to the back foot.
They mounted a sustained spell of pressure for the first time in the game and it took another good clearing header, this time by Smalling, to prevent Graham from opening his Sunderland account 19 minutes from time.
Johnson smashed a left-foot effort from distance just wide two minutes later, but Buttner forced a solid save from Mignolet and Vidic headed wide from a corner as United saw time out with few further scares.
Van Persie should have made sure deep into injury-time after Ashley Young had evaded Bramble's lunge and squared, but Mignolet made a remarkable stop to deny him.