The Frenchman ran the champions ragged as Chris Coleman's buoyant Londoners stormed to their first win over United for 39 years. Fulham deserved to win by more on an afternoon where the home side's defensive frailties surfaced again and left boss Sir Alex Ferguson - starting his two-match touchline ban - seething in the stand.
Lee Clark set Fulham on their way with his third-minute strike and United were hugely fortunate to go in level at the break from Diego Forlan's injury-time strike. But the brilliant Malbranque ran the show in the second half, firing Fulham's second in the 66th minute and providing the through-ball for Junichi Inamoto to wrap up a wonderful victory 11 minutes from time.
Louis Saha and Luis Boa Morte each could have grabbed a brace while United were only left to rue a missed Forlan effort early in the second period which could have changed the course of the game. Fulham immediately began to over-run a United midfield bearing no resemblance to that which had battled out a midweek win at Ibrox.
How Ferguson must have wished he had not rested Roy Keane and dropped Paul Scholes to the bench as Chris Coleman's confident side took control. Malbranque set up the opener with three minutes on the clock when he caught Mikael Silvestre and John O'Shea sleeping down the right and crossed to give unmarked captain Clark the simplest of chances.
The visitors maintained their early momentum and but for wayward finishing would have had a first-half hat-full. Saha's header was held by Tim Howard in the United goal while his counterpart Edwin Van Der Sar was only called into action once in the early stages when he saved well from O'Shea. Fulham were entirely unswayed by their famous surroundings and continued to look the more likely to grab the game's second goal.
They came agonisingly close in the 18th minute when Volz cut the ball back from the right and Mark Pembridge hammered a rising 20-yard effort whichclattered the crossbar before bouncing down onto the goal-line and away to safety. Then Boa Morte almost connected with a header in front of goal as Fulham completely dominated. Ruud Van Nistelrooy was being shackled so well by Volz and the towering Zat Knight while Ryan Giggs swapped flanks with the unimpressive Ronaldo.
Forlan shot across the face of goal but whenever United began to exert pressure they were undone by the fluidity of Fulham's sweeping counter-attacks. Howard was called upon to deny Saha again in the 28th minute after he had swivelled between Ferdinand and Silvestre and fired a left-foot shot which the United keeper parried. Giggs shot across the face of goal for United and Ronaldo resorted to a long-range effort which careered over the bar.
But Fulham were still given acres of space and Saha was inches wide with a free header from Clark's right-wing cross. Forlan grabbed an undeserved equaliser deep into first half stoppage time when he raced onto a Giggs through-ball and shot home to Van Der Sar's right. Quinton Fortune replaced Silvestre at the re-start - but was immediately booked by referee Riley for his bench not signalling the change in the required fashion. And although United began the second period with much more purpose their defensive frailties were soon to resurface.
Forlan should have scored his second in the 54th minute when he sprang the Fulham offside trap only to shoot horribly wide to Van Der Sar's right. But Fulham were not to be denied. O'Shea's brilliant challenge denied Saha a clear run on goal in the 63rd minute. Three minutes later Fulham were back in front when Ferdinand failed to clear Boa Morte's left-wing cross and Fortune deflected the ball into the path of Malbranque, who drove home low past Howard. Ferguson flung on Scholes in a desperate bid to turn the tide but only succeeded in giving the rampant Londoners more space to exploit. Again it was the sensational Malbranque who did the damage, knocking an inch-perfect through-ball in the 79th minute which Inamoto swept majestically over Howard to seal their wonderful win. United came close to reducing the deficit but substitute David Bellion's close-range effort hit Van Der Sar's legs.