Hours after Chelsea had established a four-point lead over United with victory at Liverpool, United once again reduced it to just one, courtesy of Nani's 28th-minute strike.
They will now head into next Sunday's final day showdown with Stoke at Old Trafford knowing that effectively only a win can give them a 19th league title, and even that will not be enough if the Blues beat Wigan at home.
Sir Alex Ferguson and his players left the north-east at least having given themselves a chance on an afternoon when they could have made things much more comfortable for themselves with striker Dimitar Berbatov passing up a hat-trick of glorious opportunities.
However, the manager's record of never having lost to a team managed by former United defender Steve Bruce remained intact, and while there is hope, he will not give up on the big prize.
Sunderland signed off their home campaign with a committed display in front of a crowd of 47,641, but on an afternoon when Fabio Capello's representatives were at the Stadium of Light, England hopeful Darren Bent had little opportunity to stake his claim for a seat on the plane to South Africa.
United ran out knowing their title bid had reached the point of no return as a result of Chelsea's 2-0 victory at Anfield, which left them needing to win at the Stadium of Light and at home against Stoke next Sunday to have any chance to overhauling the Blues.
They set about their task with some relish, but against opponents who were never likely to let them have things all their own way.
On a bitterly cold afternoon on Wearside, United created chances from the off, and it took a good fourth-minute save by Craig Gordon from Wayne Rooney, and then Phil Bardsley's block from Ryan Giggs' follow-up, to keep them at bay.
However, only Chelsea and Aston Villa had won at Sunderland this season, and the Black Cats, who were only denied a famous victory at Old Trafford in October by Anton Ferdinand's late own goal, caused problems of their own.
Central defender John Mensah lasted only 18 minutes before his injury problems struck again, but he headed wide from Jordan Henderson's 13th-minute corner, and skipper Lorik Cana was only just off target with his effort from a Steed Malbranque free-kick three minutes later.
Edwin van der Sar had to pull off a fine one-handed save to keep out Malbranque's rasping 24th-minute shot, and the home fans started to believe that a surprise could be on the cards.
However, United got their noses in front four minutes later when, after Giggs and Berbatov had caused problems on the edge of the Sunderland penalty area, the ball was fed out to Nani and he blasted a low shot past the helpless Gordon and into the bottom corner.
Bruce's men were dealt a major blow eight minutes before the break when young midfielder David Meyler was stretchered off with what looked like a nasty knee injury, and their fortunes could have taken a further turn for the worse before the half-time whistle sounded.
Berbatov failed to make the most of good work by Giggs and Rooney deep inside their own half when he allowed himself to be dispossessed by Michael Turner on the edge of the box before he could shot.
The Bulgarian was wasteful once again in injury time when Rooney once again set him up, but with just Gordon to beat, he could not hit the target.
United could, and perhaps should, have had the win wrapped up within seven minutes of the restart.
First Nani was denied his second goal of the game four minutes after the restart when Gordon made a fine save as he burst into the penalty area, and then Berbatov spooned a shot over from point-blank range with the goal at his mercy.
It was simply not the striker's day, and he could not believe his luck when he met Giggs' 56th-minute cross with a firm header just yards out and saw Gordon deflect it over the crossbar.
The home side started to make an impression as the half wore on, but with strikers Bent and Fraizer Campbell seeing little of the ball, central defenders Nemanja Vidic and Johnny Evans were rarely stretched.
But substitute Michael Carrick saw his 78th-minute effort hacked off the line by Turner and although Sunderland pushed all the way to the whistle, they could not find a way back.