On a night when the other quartet of clubs in the bottom five all lost, the Tigers also slumped to a deserved defeat at home to Millwall.
Abel Hernandez, on his return from six-and-a-half months out with a ruptured Achilles, did give City late hope with a typically predatory strike.
But the Uruguayan’s fourth goal of the season – tellingly making him Hull’s joint fourth top scorer in this increasingly miserable return to the Championship – was not enough to prevent a first home defeat under Nigel Adkins.
Not that City had any grounds for complaint at the result.
So wretched had their defending been in the first half that the Lions should really have been out of sight long before the hosts’ late rally.
Michael Dawson and Angus MacDonald simply could not cope with the movement or awareness of attacking duo Lee Gregory and Tom Elliott, whose formative careers had both been spent in Yorkshire. Time and again during a first half in which the visitors looked capable of scoring with every attack, Hull’s backline was left embarrassed.
Full-backs Ola Aina and Max Clark weren’t much better during an opening 45 minutes that saw Allan McGregor continuously having to spare his team-mates’ blushes.
MacDonald paid the price by being substituted at the interval but, in truth, any of the back four plus several others in amber and black could have had few complaints at being given first use of the showers.
Boos rained down from the sparsely-populated stands – the crowd was given as 13,524, but there was no way the KCOM was half full – at the final whistle.
Those who had braved the cold knew a big opportunity for City to boost their own survival hopes had been tossed aside.
Defeats for their fellow strugglers was the one bright spot, not least because it now seems that the usual 50 points required to stay up can be lowered with third bottom Birmingham City needing to average two points per game during the run-in to reach that target.
City’s defending was atrocious from the very start. Just 51 seconds had elapsed when George Saville held off MacDonald to open the scoring.
MacDonald’s challenge wasn’t strong enough but he was far from the only City man culpable. First, Dawson allowed himself to be dragged to the left flank and way out of position. He then missed two opportunities to clear before Jed Wallace crossed to Gregory.
Ola Aina tried to close the former FC Halifax Town striker down but his clever back-heel found Saville, who finished sweetly past McGregor.
Millwall’s second goal just after the half hour was, if anything, even worse from a Hull perspective as it came straight from a corner.
As the statuesque home defence stood and watched Ben Marshall’s delivery, Jake Cooper rose high to loop a header into the corner of McGregor’s net.
That the Tigers had no man on the post to clear the danger just about summed up their wretched efforts.
In between the two goals, McGregor twice saved his side by turning away efforts from former Leeds United junior Elliott and then Gregory.
Further chances came and went for the visitors in a first half that saw Hull embarrassed repeatedly, Elliott fatally hesitating to spurn the best of those openings when Gregory was simply begging to be played through.
Millwall continued to be wasteful after the break and this did, at least, allow City a way back into proceedings.
After striking the crossbar through Jarrod Bowen in the first half and the club’s top scorer then being denied by Jordan Archer after the restart, Hernandez entered the fray.
His first effort, after neatly bringing the ball under control, was way off target. His second, however, halved the arrears as the Uruguayan swooped on a Harry Wilson cross to convert from five yards out.
Cue a frantic finale that saw Nouha Dicko denied by Archer as McGregor did the same to Fred Onyedinma before the final whistle blew to the accompaniment of loud booing by City’s lowest crowd for a second-tier game since the final day of a 1990-91 season that ended in relegation.
Hull City: McGregor; Aina, Dawson, MacDonald (Mazuch 46), Clark; Larsson, Henriksen; Bowen, Irvine (Hernandez 57), Grosicki (Wilson 57); Dicko. Unused substitutes: Marshall, Campbell, Tomori, Stewart, Wilson.
Millwall: Archer; Romeo, Hutchinson, Cooper, Meredith; Wallace, Saville, Williams, Marshall (Onyedinma 66); Elliott (Morison 61), Gregory (Cahill 72). Unused substitutes: Martin, McLaughlin, Tunnicliffe, Shackell.
Referee: D Coote (Nottinghamshire).