The hosts dominated the first half in a match delayed by a cracked water pipe in the visitors' changing room.
The delay clearly affected United more, as the visitors were uncharacteristically sluggish, while Sunderland, so close to picking up three points a week ago at Liverpool, were industrious, creative and, at times, sublime to watch.
The Black Cats hit a post and were denied by some inspired goalkeeping by Edwin Van der Sar to keep the scores goalless at half-time.
United were let out of jail on 27 minutes when Jordan Henderson's free kick was spilled by Van der Sar, then Steed Malbranque's follow up shot hit Darren Bent, then Nemanja Vidic before being cleared.
Bolo Zenden, in for the ineligible Danny Welbeck, hit the woodwork on 37 minutes after Steed Malbranque had gone one on one with van der Sar in the 16th minute.
Such was Sunderland's domination, Simon Mignolet barely had a save to make, but did well to deny Rafael's cross which was inadvertently dropping into the net when the young Belgian plucked it out of the sky.
If United's changing rooms were a mess at kick-off, one would hate to think what the state of them would have been at half-time, with Sir Alex Ferguson clearly irked by his side's lack of application in the opening period.
United came out of the blocks with some purpose, and substitute Dimitar Berbatov thought he'd got his side ahead in the 48th minute after diverting a Scholes shot past Mignolet, but was a yard offside.
Paul Scholes got away with a blatant push on Steed Malbranque on 61 minutes, which gave Sunderland a decent chance to take the lead. Henderson's free-kick fell to Elmohamady whose first shot was blocked, and he blazed his second bite of the cherry over the crossbar.
Malbranque, a constant thorn in United's side, saw an effort deflected off Rio Ferdinand on 67 minutes.
On 73 minutes, Phil Bardsley burst into the United box, squared it for Bent but the England international skewed his shot wide.
United had their chances, On 77 minutes, Nani's 25 yard shot was well blocked by Mignolet while a Berbatov effort spun wide on 80 minutes after Hernandez' clever through-ball.
Sunderland opted to spend the last ten minutes in a 4-4-2 formation, with Asamoah Gyan and Andy Reid on as substitutes, and this almost yielded an instant reaction when from Reid's initial ball, Elmohamady pumped in a cross for Gyan which the Ghanaian rose acrobatically to fire into van der Sar's hands.
A speculative Nani effort whistled wide on 90 minutes, before Elmohamady crossed for Bent to head wide in stoppage time.
Sunderland had two more chance at the death when Henderson's shot was diverted towards goal by Bent but was cleared. United were hanging on at the end, which tells a story in itself.