Andrea Ranocchia headed a late winner as Hull came from behind to beat under-fire Slaven Bilic's West Ham side 2-1 at the KCOM.
The Hammers had taken the lead after 18 minutes when Andy Carroll expertly brought down Aaron Cresswell's long ball unchallenged and slotted past Eldin Jakupovic to open the scoring.
The goal did not dampen the Tigers' spirit and although they failed to trouble Darren Randolph in the first half, the second half saw a complete turnaround as they came alive and put West Ham on the back foot for large periods.
After bringing on Kamil Grosicki at half-time, the play immediately improved and the resurgence was kicked into gear when a flowing move was concluded by Andy Robertson slotting home after 53 minutes.
Five minutes from time, they put the icing on the cake when Ranocchia headed home Grosicki's cross at the near post to add three points to their survival total.
Firmly rooted in the bottom three, Hull were largely unchanged from the side that lost 4-0 to Everton two weeks ago. Tom Huddlestone missed out through suspension, while Oumar Niasse returned to the starting 11. Robert Snodgrass lined up against his former employers for the first time since his January move south.
The Tigers got off to a good start, knowing a win was feasible against a Hammers side who had lost their previous three in the league.
However, it was Slaven Bilic's men who broke the deadlock.
Curtis Davies and Robertson watched on as Cresswell launched a sumptuous long ball into the area. The former then mistimed his header, while the latter made no attempt to challenge Carroll as he brought the ball down with his chest and sidefooted past Jakupovic - his 50th Premier League goal.
Randolph almost gifted the home side an equaliser just before the half hour when he dribbled Sam Byram's back pass out of the area, rather than lumping it. And moments later there were calls for a penalty when he lunged at Abel Hernandez when the striker dared to try to dispossess him.
Lanzini soon tried to bend an effort into Jakupovic's far post but the stopper somehow managed to get fingertips to it.
It was at half-time that the game changed. Marco Silva has overseen a revolution at Hull in his short time at the club and continued with a substitution that turned out to be a masterstroke: taking off Davies and replacing him with Grosicki.
Just eight minutes into the second half, the change paid off. There were a series of passes just outside the West Ham area before the flowing move made its way to the substitute. He knocked the ball into the path of Robertson, who dragged the ball out wide, before slotting home from close range.
Carroll had a bullet header claimed just before the hour mark, before Lanzini hit a cross-field pass to Sofiane Feghouli at the back post. Had Carroll been on the end of the cross, perhaps this game would have had a different ending.
But it didn't. The Hammers struggled to batten down the hatches when Alfred N'Diaye hit the post and five minutes before the end of normal time, the KCOM roof was almost lifted off when Ranocchia met Grosicki's corner.
The defender, who had been in the wars all afternoon, leapt highest at the near post to nod past Randolph and hand the Tigers an important win in their fight against the drop.
Hull: Jakupovic (7), Ranocchia (8), Davies (5), Maguire (7), Elmodamady (7), Markovic (7), N'Diaye (7), Clucas (6), Robertson (8), Hernandez (6), Niasse (6)
Subs: Grosicki (8), Maloney (5), Henriksen (5)
West Ham: Randolph (5), Byram (6), Fonte (5), Collins (6), Cresswell (7), Kouyate (6), Lanzini (6), Feghouli (6), Ayew (5), Snodgrass (6), Carroll (7)
Subs: Masuaku (6), Calleri (5), Fernandes (5)