Both sides had made two changes following last weekend's FA Cup third round stalemates.
With Lucas Neill (hamstring) still not recovered from the injury he picked up against Manchester City and John Pantsil away on African Cup of Nations duty, Curbishley recalled Jonathan Spector and fit-again Freddie Ljungberg.
Frenchman Julien Faubert also found himself in the Upton Park dug-out for the first time since his £6.1million summer arrival from Bordeaux.
Lowly Fulham recalled Steve Davis and Chris Baird in place of Alexei Smertin and Hameur Bouazza following their disappointing draw with Bristol Rovers, while ex-Hammer Jimmy Bullard was named on the bench for the first time in 16 months.
Without any win since November 3, Fulham got off to a dream start when Davies whipped over a seventh-minute free-kick which missed everyone in the crowed penalty area before nestling in the far corner of Robert Green's goal.
Jolted by that early blow, West Ham struggled to get going, but as the half-hour mark neared Ljungberg curled his right-wing cross around ex-Hammer Paul Konchesky and Ashton beat substitute Aaron Hughes to claim his sixth goal of the season with a thumping six-yard header.
With the confidence now visibly draining from the visitors, only the defiance of Antti Niemi prevented Curbishley's side from taking the lead before the break.
Indeed, the formidable Finn thwarted Ferdinand, before twice denying Ashton with spectacular saves and then frustrating Carlton Cole from close range too.
With Curbishley giving his troops that half-time wake-up call, West Ham emerged for the restart looking far more determined and, after Ashton hooked across goal, Konchesky found himself nodding Cole's header off the line.
Luis Boa Morte then stepped from the bench and within minutes of his arrival, he combined with Ljungberg to win the 68th minute corner that was ultimately destined to sink his former team-mates.
For when the flag-kick was cleared and then nodded back into the Fulham area, the determined Noble refused to give up the cause as he hooked the escaping ball back from the goalline and into the danger zone where Ferdinand drilled a rising eight yarder beyond the helpless Niemi.
Having seen three points turn to none, Fulham fruitlessly went in search of a leveller as Mark Noble scrambled Clint Demspey's header off the line, before Baird then nodded over.
But in the end, the highlight of the closing stages for both sets of fans was the welcome sights of Bullard and then Faubert finally stepping from the bench.