Steve Sidwell’s 19th-minute goal gave underdogs Fulham a shock lead against the champions.
The Whites have got men behind the ball and defended well before and since scoring with their first attack of the match.
Lewis Holtby chipped the ball forward and Sidwell sneaked in unmarked to fire home from 10 yards.
Robin van Persie then missed a great chance to equalise for Manchester United when he blazed over after being found by Rafael’s right-wing cross.
And as the visitors absorbed more pressure, Maarten Stekelenburg produced fine saves to keep out Ashley Young’s header and Michael Carrick’s driven shot.
But Fulham remained a threat on the break and ex-United man Kieran Richardson squandered a golden opportunity to make it 2-0 by shooting wastefully over following good work by Muamer Tankovic.
United kept up the pressure after half-time and Stekelenburg pulled off another superb save, this time denying Wayne Rooney from close range.
And Fulham appeared to have a let-off when United appealed in vain for a penalty after the ball struck the hand of centre-back Dan Burn, who has been outstanding alongside Johnny Heitinga.
Former United coach Rene Meulensteen selected a surprising line-up on his return to Old Trafford.
The Fulham boss, whose side are bottom of the Premier League, opted for Tankovic. 18, as a lone striker, with Holtby supporting the Swedish youngster from midfield.
Record signing Kostas Mitroglou was not in the matchday squad but deadline day arrival Heitinga is making his debut and Ryan Tunnicliffe, recently signed from United, was also given a starting place.
Sidwell is captaining the side, with Scott Parker and Brede Hangeland both among Meulensteen’s substitutes.
Fulham: Stekelenburg; Riether, Burn, Heitinga, Riise; Tunnicliffe, Sidwell, Kvist, Richardson; Holtby, Tankovic (Bent 45).
Subs: Stockdale, Hangeland, Kacaniklic, Duff, Cole, Parker.