Hull stunned Sky Bet Championship promotion-chasers Sheffield United with a 3-0 win at Bramall Lane to climb out of the bottom three.
Matt Crooks gave the Tigers an early lead and substitute Matty Jacob struck in the second half before the Blades’ misery was completed by defender Harrison Burrows’ late own goal.
Ruben Selles’ side sealed their third straight away win and it was Hull’s first at the South Yorkshire ground since 2010.
The Blades, who had not lost to Hull in their previous seven league encounters, slipped to their fifth Championship defeat of the season and missed the chance to leapfrog Leeds back into top spot.
Blades striker Ben Brereton Diaz went close to an early opening goal in his first start since returning to the club on loan from Southampton this week, with the recalled Ivor Pandur turning his angled shot away for a corner.
But Hull broke from a corner to take a shock sixth-minute lead following a rare Blades defensive lapse this season.
Adam Gilchrist miscued his attempted clearance and former Middlesbrough midfielder Crooks – signed from Salt Lake City and one of six new January signings for the Tigers – pounced to curl home an excellent finish.
It was only the sixth goal the Blades have conceded at Bramall Lane in the Championship this season, while they have kept 16 clean sheets in all.
United also handed a debut to Republic of Ireland striker Tom Cannon, signed from Leicester for a reported fee of around £10million earlier on Friday.
But after the Blades had laboured to a 2-1 win at Swansea on Tuesday this was another disjointed display.
Former Blackpool striker Kyle Joseph made his Hull debut and on-loan Leeds forward Joe Gelhardt his second start and they both helped make the visitors a threat on the counter-attack.
The Blades went on the offensive at the start of the second period, Sam McCallum’s low shot deflected wide by Hull skipper Alfie Jones before Pandur tipped Callum O’Hare’s looping header over the crossbar.
Hull’s latest recruit Eliot Matazo, signed from Monaco earlier on Friday, and Jacob replaced Crooks and Finley Burns before the hour mark, while Wilder made three changes.
McCallum, Brereton Diaz and Andre Brooks were replaced by Rhian Brewster, Vini Souza and Tyrese Campbell and the latter was denied an equaliser by the linesman’s flag moments later.
But Hull then doubled their lead. The home side failed to clear Gelhardt’s cross and when another was sent back in by Cody Drameh, fellow full-back Jacob reacted quickest to divert the ball into the bottom corner.
The Blades cranked up the pressure in the closing stages but found clear-cut chances hard to come by.
Campbell fired over from close range and Burrows blazed off target, while plenty in the home seats had called it a night before the latter diverted substitute Joao Pedro’s low cross into his own net.
