Martin O'Neill's side made their numerical advantage count in the second half after Fulham defender Brede Hangeland was sent off in the first half.
Steven Fletcher set Sunderland on their way with the opener five minutes into the second half with his sixth league goal of the campaign.
Although substitute Mladen Petric drew Fulham level just past the hour mark further goals from Carlos Cuellar and a superb effort from Stephane Sessegnon made the game safe for Sunderland to ease the pressure on O'Neill.
After a quiet opening period the game burst into life just past the half-hour mark when Hangeland was sent off for a dangerous tackle on Lee Cattermole.
The Fulham captain appeared to leave the ground as he went in two-footed on Cattermole and referee Lee Probert deemed it a straight red card offence.
The second half began in lively fashion with Sunderland breaking the deadlock on 50 minutes just seconds after Fulham struck the woodwork.
John Arne Riise saw his shot deflect off Phil Bardsley and onto the crossbar and the play switched straight to the other end as Adam Johnson picked out Fletcher with a brilliant through ball and the striker superbly controlled the ball before poking it past Mark Schwarzer.
Fulham, who lost Alex Kacaniklic to injury in the first half, suffered another injury blow on the hour mark when Bryan Ruiz was forced off with a hamstring problem to be replaced by Petric and the substitute had a chance to score straight away when he got in behind the Sunderland defence, but he lifted his shot over the top.
A minute later Johnson was denied a second goal for Sunderland when he saw his curling shot from the edge of the box turned round the post by Schwarzer at full stretch.
Fulham drew level on 62 minutes through Petric as he converted Duff's cross from close-range as the Sunderland defence appealed in vain for an offside flag against Duff.
Parity proved short-lived as with Fulham down to nine men as Petric received treatment off the field after injuring himself scoring the equaliser Cuellar restored Sunderland's lead three minutes when he rose above Steve Sidwell to head home Johnson's corner.
Sunderland gave themselves a two-goal cushion 20 minutes from time with a sublime goal from Stephan Sessegnon as the striker netted his first goal of the season.
Referee Probert played a good advantage after Danny Rose was injured in the build-up and Sessegnon found space outside the box before unleashing a stunning shot into the top corner past a stranded Schwarzer to send the visiting fans into raptures.
Fulham refused to lie down and Sunderland were indebted to Simon Mignolet in the closing stages as he made two fine saves to keep out Sidwell and Petric as the home side threatened a comeback.