Carlos Bocanegra's last-minute goal crushed 10-man Tottenham's hopes of gaining a point at Craven Cottage. Martin Jol's side defended for their lives after Michael Dawson was sent off after 72 minutes.
The former Nottingham Forest defender received two yellow cards, both for fouls on Heidar Helguson and Spurs were stung at the death.
After he went close in the first half, no one was able to stop Bocanegra's header from a Simon Elliott free-kick.
The Cottagers' new signing Michael Brown, captured from their opponents, saw his new employers make more headway in the first half.
The returning Andy Reid may have fired narrowly over in the opening minutes but Fulham seemed more constructive going forward and, had it not been for the resolution of Ledley King and Dawson, they would have given themselves an interval lead.
When they did manage to get through, Paul Robinson demonstrated why he is Sven-Goran Eriksson's first choice between the posts.
He dived to his left and flung out an arm to divert Bocanegra's close-range header and then pushed Brian McBride's volley away after the American forward had swivelled in the area.
Up front, Spurs lacked imagination and, despite utilising Aaron Lennon's pace down the left, there was not the cutting edge expected from a team chasing a Champions League spot.
Spurs did push on after the break but the absence of Mido's power up front limited their options.
A shout for a penalty against Luis Boa Morte after the Fulham captain tackled Jermaine Jenas was dismissed.
However, the impact which Jermain Defoe might have had up front when he replaced Grzegorz Rasiak was hit by Dawson being sent off with 18 minutes remaining.
The defender marked the anniversary of his move to White Hart Lane in an unwelcome fashion when, having been booked for a foul on Helguson earlier in the half, he was red carded when he upended the Iceland striker on the edge of the box.
Defoe did manage to force a save out of Antti Niemi with a curling effort but the replacement of Lennon with defender Anthony Gardner signified a change of priorities after Spurs went down to 10 men.
But just when it seemed Spurs would be able to hold onto a point, Bocanegra pounced, connecting with Elliott's free-kick and nodding home from eight yards.
Fulham manager Chris Coleman: "It was a typical London derby and we had far more shots on goal than they did so we deserved to win. "They had plenty of possession but Paul Robinson was by far the busier goalkeeper.
"After the sending-off, we got impatient and we didn't use the extra man.
"We have now won three games out of four and I would take that out of the next four."