Aleksandar Mitrovic’s 38th Championship goal of the season took Fulham a step closer to sealing promotion back to the top flight.
Mitrovic missed an early chance when he dragged an effort wide after an error by Middlesbrough defender Dael Fry.
But the Serbian striker broke the deadlock in emphatic fashion with 16 minutes remaining.
Harry Wilson swung in a brilliantly-delivered free-kick and Mitrovic headed beyond former QPR keeper Joe Lumley and into the far corner of the net.
It means Mitrovic needs just five more to break Guy Whittinhgham’s 29-year record for goals scored in a second-tier season.
Josh Coburn missed a great chance for Boro when he headed wide of the target late on, and Duncan Watmore also squandered an opportunity to equalise when he fired over in stoppage time.
The win leaves Fulham 11 points clear at the top of the table.
Fulham: Rodak, Tete, Tosin, Ream, Bryan (Robinson 82), Reed, Chalobah (Onomah 64), Wilson, Carvalho, De Cordova-Reid (Kebano 64), Mitrovic.
Subs not used: Gazzaniga, Hector, Seri, Muniz.