Fabio Borini's winner lifted Sunderland's hopes of Capital One Cup glory as Manchester United slipped to a third successive defeat.
The Italian's 65th-minute penalty handed Gus Poyet's men a precious 2-1 first-leg advantage in their Semi-Final showdown with United.
Borini nervelessly converted to condemn the visitors to three defeats in a row for the first time since May 2001, and the result will send Sunderland to Old Trafford on January 22nd with high hopes of reaching their first major final since 1992.
The Black Cats, who remain rooted to the foot of the Premier League table, had taken the lead at the end of the first half as Ryan Giggs scored an own goal.
The 40-year-old proved a central figure in the match, but not in the way he might have wished as his luck deserted him.
Adnan Januzaj's 38th-minute strike, which would have given United the lead, was chalked off because the Welshman was offside when the 18-year-old's initial shot hit him in front of goal, and it was Giggs who handed the home side the advantage in first-half injury time.
The veteran found himself patrolling at the far post when Wes Brown drilled Sebastian Larsson's free-kick in his direction and as Phil Bardsley attempted to dispatch it, he turned it into his own net.
The visitors dragged themselves back into the game when returning central defender Nemanja Vidic struck with a towering 52nd-minute header, but the drama was far from over.
Later in the second half, substitute Adam Johnson lured Tom Cleverley into a ill-judged challenge on the edge of the box and, after consulting his assistant, referee Andre Marriner pointed to the spot to hand Borini his big chance, which he took confidently.
The tie, of course, is far from over and United, who were watched by their former manager Sir Alex Ferguson and director Sir Bobby Charlton, may approach the second leg confident of clawing back the slender deficit.