Bottom side Sheffield United stunned Luton Town 3-1 at Kenilworth Road and denied the high-scoring Hatters a golden opportunity to pull four points clear of the Premier League drop zone on Saturday.
The hugely important first away win of the season left the Blades last but level on 13 points with Burnley.
Starting as favourites for once after hitting four goals past Newcastle United and Brighton & Hove Albion in each of their last two games, Luton dominated possession but were 2-0 down at the break.
Cameron Archer slotted the visitors ahead in the 30th, making up for a big miss moments earlier, after outpacing Gabriel Osho down the right side.
James McAtee then doubled the tally for Chris Wilder's side from the penalty spot six minutes later after a VAR check on Reece Burke's debatable handball.
Luton captain Carlton Morris made it 2-1 from another penalty for handball by Vinicius de Souza, who then hit back on the break in the 72nd to restore the two goal advantage.
Sheffield defended impressively to hold on through nine minutes of extra time.
The result made up for a 3-2 loss in the reverse fixture in December.
Luton stayed 17th on 20 points and one clear of Everton, who lost 2-0 at Manchester City.
Sheffield had to overcome an early setback when Rhys Norrington-Davies was injured after just three minutes and had to be substituted.