Katie Chapman’s header cancelled out an early Stephanie Roche strike before Fran Kirby added a second to give Chelsea all three points.
Despite a positive start, worries gripped Chelsea in the sixth minute when Beth Mead battled her way onto the ball just outside the box before setting up Roche, who was in acres of space, to score.
However, this woke the hosts from their slumber and within two minutes they equalised through Chapman, the skipper heading in Karen Carney’s free-kick.
Waves of attacks came from Chelsea and Sunderland’s defence cracked in the 21st minute as Eniola Aluko’s cross was nodded past Rachael Laws by Kirby.
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The host’s half-time lead could have been larger, but good chances were spurned by Kirby, Aluko and Niamh Fahey.
After the break it was Chelsea who stayed in charge with Aluko going close, forcing a save from Laws after weaving past a numerous challenges.
Aluko forced two more excellent saves from Laws and Ji So-Yun, Gemma Davison, Carney and Kirby also went close.
Sunderland rarely threatened going forward, with a deflected Rachel Furness shot the closest they came to troubling Hedvig Lindahl.
Chelsea (4-2-3-1): Hedvig Lindahl; Hannah Blundell, Niamh Fahey, Gilly Flaherty, Claire Rafferty (Aba Borges 26); Katie Chapman, Ji So-Yun (Drew Spence 70); Gemma Davison (Beth England 80), Karen Carney, Enolia Aluko, Fran Kirby.
Subs not used: Rebecca Spencer, Millie Bright, Jade Bailey, Laura Rafferty.
Sunderland (4-5-1): Rachael Laws; Danielle Brown, Stephanie Bannan, Hayley Sharp, Victoria Williams; Lucy Staniforth, Brooke Chaplen, Kelly McDougall (Rachel Furness 67), Keira Ramshaw (Krystle Johnstone 61), Stephanie Roche; Beth Mead.
Subs not used: Hilde-Gunn Olsen, Abbey Joice, Megan Beer, Charlotte Potts, Abby Holmes.
Bookings: Furness 75, Brown 82
Referee: Robert Whitton. Attendance: 1,397
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