West Ham capitalised on a Bernd Leno-Calvin Bassey blunder to earn a valuable 1-0 win at Craven Cottage - but remain in the Premier League relegation zone.
Nottingham Forest's unlikely draw at title-chasing Man City means Nuno Espirito Santo's side are still third-bottom - but their gap to safety is now only four goals on goal difference, after Crysencio Summerville pounced to win this London derby.
Their supporters certainly believe now. They chanted 'We are staying up' during their celebrations after full-time before a rendition of 'Tottenham Hotspur, we're coming for you', having sucked their rivals right into this survival scrap. Spurs, who are now only a point ahead, host Crystal Palace on Thursday.
With West Ham facing Man City and Aston Villa next in the Premier League, it was vital they bounced back from their heavy loss at Liverpool on Saturday. And they did just that, with a helping hand from their hosts.
Fulham - who were chasing a third-straight league win to boost their European qualification dream - had been sloppy and fortunate not to give up a first-half penalty when Alex Iwobi leant his arm into a near-post corner. And the mistake from Leno and Bassey summed up their lack of sharpness.
Leno bumped the ball out of his area but then left it for Bassey. Bassey left it for Leno. Summerville sparked into life, took a smart touch and then arrowed the ball into the net to the delight of the travelling fans.
Fulham - who had seen a penalty awarded their way overturned earlier in that second half, when it was eventually judged Tom Cairney fouled Taty Castellanos while shooting and not the other way around - threw bodies forwards in search of a response.
But Rodrigo Muniz's header looped over and Mads Hermansen - who had saved brilliantly from Josh King on the stroke of half-time - produced another stunning stop to deny Timothy Castagne and preserve West Ham's clean sheet and earn three precious points.
Fulham - without star man Harry Wilson and his final-third quality - missed the chance to go level on points with eighth-placed Everton and sit 10th.
West Ham's Crysencio Summerville to TNT Sports:
"We have to fight till the end, that is what we did. Everyone knew it was a difficult place to come to.
"We have to keep going now. The only way is up now. Our fans are our 12th man on the pitch."
On his goal: "It was a good pressing move and I needed to take composure. I am happy I could finish the action.
"The coach said to us we have to be composed. I took the advice and I'm happy!"
