Jonathan Stead scored the winner 15 minutes from time after Rovers had twice thrown away the lead.
Andy Cole had given the visitors the lead halfway through the first half, before Collins John struck a double to turn the game on its head before the break.
The second from John on the stroke of half-time provided a real test for Rovers, but they came out with all guns blazing to restore the lead within five minutes as John Douglas and Lorenzo Amoruso scored in quick succession.
But Luis Boa Morte's wonder-goal begged the question again as to whether Rovers have enough fight for survival.
And 21-year-old Stead provided the answer as his 20-yard strike zipped off the ground and into the net to give them a much needed win.
Early on Rovers were furious as Zat Knight clashed with Stead off the ball. The young striker had to be treated as defender Amoruso led a group of Rovers players to hound referee Mike Dean into taking action.
However their claims were dismissed as he allowed the game to go on following a discussion with his assistant.
Moments later Amoruso attempted to take out his frustration with a long-range effort but his 30-yard free-kick flashed just over the bar.
Before long Rovers were in front. On 23 minutes Tugay found Andy Cole with a superb long ball which the Rovers striker took in his stride as he drilled the ball past van der Sar from close range.
But Fulham levelled within three minutes. Rovers failed to deal with a deep Sean Davis free-kick into the box and Martin Djetou thumped a volley against the underneath of the crossbar.
As the ball bounced out it was the Cottagers who reacted quickest through John and then Carlos Bocanegra but it was new fans favourite John who will claim the goal as he knocked the ball past Brad Friedel and over the line.
The goal rocked Blackburn and two chances in quick succession followed.
First Friedel saved from Steed Malbranque's left-footed effort, and from the corner that followed the American keeper was again at this best to save from a Knight header.
Fulham were really running the game and as half-time approached it seemed only a matter of time before they scored.
And the inevitable was soon reality as Fulham scored two minutes into first-half stoppage time. Malbranque curled in a free-kick and John stole in front of Gresko to side foot the ball past Friedel.
Whatever the boss said at half-time worked wonders as Rovers came out for the second half with all guns blazing and turned the game on its head once again.
Douglas pounced to score his first senior goal as he met Gary Flitcroft's header to send an unstoppable shot past the Fulham keeper from eight yards.
And incredibly Rovers took the lead minutes later through a thunderous Amoruso free-kick. From almost 35 yards the defender hit a shot through the Fulham wall and van der Sar could only get a hand to the shot before it hit the back of the net to send the visiting fans delirious.
Stead went close to a fourth on 54 minutes before Boa Morte scored a wonder-goal to pull the scores level once again.
Boa Morte picked the ball up deep inside his own half and played a one-two on halfway before dribbling 40 yards and side footing past Friedel.
It was then left to young Stead to put his mark on the game. On 75 minutes from Cole's knockdown he hit a superb drive from outside the area and into the net to boost their hopes of staying in the top flight.
Fulham: Van der Sar, Volz, Djetou, Goma, Bocanegra, Sean Davis (Petta 79), Legwinski, Knight, Malbranque (McBride 84), John (Hayles 87), Boa Morte. Subs not used: Crossley, Pearce.
Goals:
C.John (26) (45)
L.Boa Morte (60)
Blackburn: Friedel, Neill, Amoruso, Short, Gresko, Andresen, Flitcroft, Tugay, Douglas, Cole (Emerton 89), Stead (Gallagher 90). Subs not used: Enckelman, Reid, Johansson.
Goals:
A.Cole (23)
J.Douglas (49)
L.Amoruso (51)
J.Stead (75)
Attendance: 13,981
Referee: M Dean (Wirral)