The sloppy play from Manchester United made them drops vital point again as the Black Cats keeps their hopes of staying in the league with just 1 point to cross the relegation zone.
Whabi Khazri strikes a low free-kick just 3 minutes of play to give Sunderland the lead. But the informed and vibrant Antony Martial restored parity at the 39th minutes to keep United hopes alive as they head to the break on level point.
But with eight minutes to play, the Black Cats did find their breakthrough, as Lamine Kone crashed in a low header from a corner that eventually crossed the line after a rebound off the back of the unfortunate De Gea.
With Sunderland winning the game 2-1, their on fired coach Sam Allardyce jugs to the pool with smiles.
