The Lady Black Cats frustrated the visitors early on but Rafferty managed to keep Karen Carney’s cross down as she volleyed past Rachael Laws.
Rafferty then doubled Chelsea’s advantage three minutes before the break as she tapped home from close range before Gemma Davison unleashed an arrowed strike into the bottom corner to make Sunderland rue their missed chances.
Second-half strikes from Millie Bright and Ji So Yun proved to be enough as Chelsea upstaged Sunderland to keep the heat on league leaders Manchester City.
Going into the game Carlton Fairweather noted a reaction was vital following the Ladies’ disappointing defeat at Arsenal on Saturday.
Unfortunately for the hosts, Chelsea arrived on Wearside unbeaten on the road since their last trip to the Hetton Centre when Beth Mead struck an impressive hat-trick as Sunderland dismantled Chelsea 4-0.
Since then the Blues’ prowess has been rarely tested on the road and that shone through in the early exchanges as confidence oozed from the visitors.
So Yun found space inside the area after a quick break but failed to hit the target before Carney almost caught Laws unawares as her attempt flicked the outside of the post.
Sunderland weren’t without their chances and their regimented and dogged approach almost paid off when Brooke Chaplen clattered into Chelsea’s onrushing stopper as the midfielder looked to latch onto a stray ball.
However, as the clock ticked into the 29th minute Sunderland’s resolve was finally breached as Rafferty guided Carney’s deep cross into the roof of the net with a scintillating side-footed volley. Sunderland responded well and should’ve levelled when Beth Mead managed to wriggle her way through Chelsea’s backline, but her finish wasn’t there to match her run and she fired over.
From there Chelsea gained a tight grip on the game and doubled their advantage in the 42nd minute when Rafferty poked home an arrowed ball across the face of goal.
Two minutes later Davison added a third as she got the better of Tori Williams before her drilled shot flew into the bottom corner.
Sunderland returned for the second period with a similar fight and determination they showed in the opening stage of the match.
But while the hosts were full of running, Chelsea continued to move the ball quickly and forced Laws into making a number fine saves.
In the 72nd minute, Chelsea’s dominance paid off and two long-range efforts – from Bright and then So Yun - in five minutes saw Chelsea build an unassailable lead.
Sunderland battled on defiantly until the end but Chelsea’s class continued to shine through as they left Wearside with all three points.
Sunderland Ladies starting XI: Laws, Brown, Bannon, Willams, Sharp, Furness, Chaplen, Joice (Holmes, 78), Hill, Roche (Ramshaw, 46), Mead (Potts, 79).
Unused subs: Olsen, McDougall.