Sunderland beat Manchester United 2-1 at the Stadium of Light to go within a point of safety.
It was a dramatic afternoon at the Stadium of Light, with goals from Wahbi Khazri and a Lamine Kone header - deflected in by David De Gea - enough to seal a priceless three points.
Sam Allardyce's first chance to improve the Sunderland squad in the market has immediately prompted an improvement in the Black Cats' fortunes after maiden goals for January buys Wahbi Khazri and Lamine Kone secured a huge 2-1 victory over Manchester United.
The Stadium of Light success was thoroughly deserved for Sam Allardyce's side, who were the better side other than a 20-minute spell at the end of the first half.
Khazri got Sunderland off to a dream start early on when his inswinging free-kick found the bottom corner, but United pulled level just before the half-time after a lovely finish from Anthony Martial on the rebound.
Sunderland were on top after the break, but were denied by several outstanding saves from United keeper David De Gea.
But with eight minutes to go, Kone headed home from a Khazri corner to secure Sunderland's first home Premier League win over United since 1997.
Sam Allardyce, Sunderland manager:
"Really good performance today with the right result, and everyone who played on that field deserves a lot of credit for the way they've managed Manchester Utd and how often we've taken the game to them, and created lots of chances to win this game, and finally got the goal that did win it from Lamine.
"Our new players have made a massive contribution since they've been here but no more so than today with Wahbi's goal off the free-kick and then his corner for Lamine's winner.
"Hopefully that will bode well for the rest of the season."
Louise van Gaal, Manchester United manager:
"I told the team, they had to recognise it as well. But the main reason is always in a match you will be compared with your opponents in aggression.
"And I think that Sunderland played with more aggression because they played with direct balls. Second balls are very important to win and they won a lot of them.
"We started very badly, the first 20 to 25 minutes but the second half of the first half we could cope with that aggression and we had our positional game."
Sunderland: Mannone, Yedlin, O’Shea, Kone, van Aanholt, Kirchhoff (Rodwell 15), Cattermole (Toivonen 85), M’Vila, Khazri, N’Doye, Defoe (Borini 71).
Subs not used: Brown, Matthews, Pickford, Honeyman.
Booked: Yedlin (38), O'Shea (45)
Manchester United: De Gea, Darmian (Love 38), Smalling, Blind, Borthwick-Jackson, Schneiderlin (Keane 86), Carrick, Lingard (Memphis 62), Mata, Martial, Rooney.
Subs not used: Romero, Weir, Pereira, Herrera.
Booked: Rooney (46), Mata (58), Carrick (59)
Who was your man of the match?
There were several contenders with John O'Shea, Lamine Kone and Wahbi Khazri all outstanding at the Stadium of Light.