Leeds suffered a damaging defeat in their bid to remain in the Premier League as a second-half penalty secured victory for Sunderland at Elland Road.
In a game that had lacked quality for long periods, the decisive moment came in the 70th minute when the Black Cats were awarded a spot-kick for handball.
It came after referee Stuart Attwell was advised to go to the pitchside monitor by the video assistant referee (VAR) after Leeds skipper Ethan Ampadu appeared to move his arm towards the ball inside the box after initially blocking an attempt by Wilson Isidor.
Habib Diarra, subject of a transfer bid by Leeds last summer, was relieved when his poorly-struck penalty hit Karl Darlow on the hip, but the ball squirmed back over the keeper and into the net.
It was frustrating for the hosts, particularly after they had a Joe Rodon header disallowed for offside just minutes earlier.
Leeds had been the better side until then, but struggled to find quality in the final third, with Sunderland seemingly content to slow the game down.
Their best moment came in the first half when Anton Stach’s free-kick was pushed behind by Melker Ellborg, who was making his debut in goal following a February move in the absence of the injured Robin Roefs.
The Swedish keeper also saved well from Jaka Bijol’s close-range header in 12 minutes of added time.
A win for 15th-placed Leeds would have provided a huge boost to their survival hopes, but third-bottom West Ham could cut the gap to three points if they win at Fulham on Wednesday.
Sunderland, meanwhile, are 11th on 40 points after winning away in the league for the first time since October at Chelsea.
Leeds analysis: Farke’s men fail to show quality in final third
This was a frustrating result for Leeds in more ways than one.
Firstly there was the result, which could leave them just three points above the drop zone by the end of the week if results elsewhere go against them.
Secondly was their annoyance with the officiating, with the home fans clearly aggrieved at what they felt was Sunderland time-wasting from early on, and a perceived lack of action against that.
But, ultimately, the home side did not do enough in a game that provided a golden opportunity for them to take a huge step towards securing another season of top-flight football.
They had just four of 18 shots on target and did not test Sunderland’s debutant keeper Ellborg enough.
Rodon’s disallowed effort was a big turning point, and boss Daniel Farke made a raft of attacking changes near the end, but the visiting defence held firm.
Sunderland analysis: Black Cats end March madness
It may not have been pretty but this was an effective away performance by Sunderland that keeps them in the frame for a finish in the European places.
Eyebrows may have been raised when boss Regis le Bris opted to use this game to hand Ellborg his debut in goal, but the 22-year-old acquitted himself well, particularly in handling the jeers from the home fans when he was deemed to have been time-wasting.
He managed to deal with Leeds’ efforts comfortably too as his side gained a battling third win in 13 league games.
Sunderland undoubtedly got a degree of fortune for the winner, but looked a more solid and dangerous side when captain Granit Xhaka was introduced 11 minutes into the second half.
It has been an impressive top-flight return for the Black Cats, who have now reached the 40-point target that Le Bris wanted and usually guarantees another season of Premier League football.
They also finally ended their March madness, having been winless in 17 previous top-flight games during this month since beating QPR in 2012.
What’s next for these teams?
Focus switches to the FA Cup fifth round for both these teams on Sunday, 8 March as Leeds host Norwich (16:30 GMT), while Sunderland are at League One Port Vale (13:30 GMT).-BBC
