Sunderland took the lead through an own-goal by Ryan Giggs on the stroke of half-time, only for Nemanja Vidic to equalise just after the break. Sunderland then sealed the win with a Fabio Borini penalty, awarded when Tom Cleverley was adjudged to have brought down Adam Johnson.
The hosts started the game well, with Seb Larsson and new left-back Marcus Alonso in particular providing some dangerous balls into the box. Indeed, Borini had the first proper effort on goal, swivelling on the edge of the area to shoot straight at David De Gea in the United goal.
However, United came back into the game, largely thanks to a tactical switch by David Moyes. Adnan Januzaj started the game on the left wing with Ryan Giggs in the middle, but around the 20 minute mark Moyes switched the two men around, allowing the youngster to exert far more control and influence over the game.
And he showed that almost straight away, winning a free-kick from which United almost scored. Januzaj himself did have the ball in the net, but his effort was ruled out for offside.
Sunderland took the lead in the closing seconds of the first half. A free kick was hurled over to the far post, Brown knocked it back into the middle where a combination of Bardsley and Giggs bundled it into the net.
United equalised not long after the break, when Tom Cleverley put a deep corner to the far post, where Vidic was there to head in past a static Mannone.
But the lead didn't last long, as substitute Adam Johnson won a penalty from a clumsy challenge by Cleverley just inside the area. Borini stepped up and hit the penalty high into the net and to De Gea's left.
United piled the pressure on in the latter stages, but Sunderland hung on to take a 2-1 lead into the second leg at Old Trafford.
PRE-MATCH - So reasonably strong teams named by both managers. It will be interesting to see how United line-up - it's possible in that team that Adnan Januzaj might play in the middle, behind Danny Welbeck. Or it could be a straight 4-5-1 with Giggs, Cleverley and Carrick in the middle.
45 - GOAL! BARDSLEY GIVES SUNDERLAND THE LEAD. After a disputed free kick is hurled over to the far post Brown knocks it back into the middle where a combination of Bardsley and Giggs bundles it into the net.
52' - GOAL - VIDIC EQUALISES FOR UNITED! Simple enough, that. Cleverley puts a deep corner to the far post, where Vidic is there to head in past a static Mannone.
63' - PENALTY TO SUNDERLAND! Johnson runs into the box from the right, and Cleverley makes the challenge. How much contact there was is hard to tell, but the kick is given.
65' - GOAL! - BORINI PUTS IT AWAY! High and to the keeper's left, and it's 2-1 to Sunderland.
That is the first time United have lost three games in a row since the latter stages of the 2000/1 season - and the first time they have lost three inside a week since 1992.
United have now lost 25% of their matches this season - 8 of 32. Last season they lost only 10 of 54.
Sunderland had 43% possession, United had 57%.
Sunderland's illogical season - Ahead in the semi-final of the Capital One Cup, in the fourth round of the FA Cup, but stone bottom of the Premier League with only three wins to their name all season. Football is an illogical business at the best of times, but Gus Poyet's side need to take some of their cup form into the league, otherwise it could be a seriously mixed season for the Black Cats.
MAN OF THE MATCH
Adnan Januzaj, Manchester United - Despite United's defeat, the youngster was superb for David Moyes' side, with everything good that they did going through him. It's ludicrous that United are so reliant on one so young, but he really does often look like the only player who can create anything for the Champions.
SUNDERLAND: Mannone 7, Bardsley 6, Alonso 8, Brown 7, O'Shea 7, Larsson 6, Cattermole 5, Ki 6, Giaccherini 5, Borini 7, Fletcher 6. SUBS: Johnson 7, Altidore 5.
MANCHESTER UNITED: De Gea 6, Rafael 6, Vidic 7, Evans 6, Evra 7, Valencia 6, Carrick 6, Cleverley 4, Januzaj 8, Giggs 7; Welbeck 6. SUBS: Smalling 5, Hernandez 5, Fletcher 7.
THE MATCH IN A TWEET