Lewis Mansell condemned Fulham to their second defeat of the week as Blackburn Rovers won 1-0 at Motspur Park to remain top.
The 20-year-old striker latched on to a poor back-pass by Tayo Edun and slotted into the bottom corner on 21 minutes.
Fulham had earlier come close through Michael Elstone, but Andrew Fisher saved well from Aron Davies.
Blackburn have 31 points, one place and a point above Aston Villa, while defeat leaves Fulham fifth on 26 points.
See: Fulham report
Next fixtures
Fulham: 17 Feb v Stoke (A) PL2
Blackburn: 9 Feb v Reading (H) PL2