Swansea secured a fourth successive win in the Championship as they held off a spirited Sunderland fightback.
Recalled defender Harry Darling doubled the advantage when he poked home a second in first half stoppage time.
Jack Clarke's fine run and finish gave the visitors hope, but Swansea held firm despite the visitors being the better side after the break.
The Swans remain in the Championship play-off spots after collecting 12 points from 12, while the Black Cats fall to 12th despite a spirited second-half display that almost saw them claim a share of the spoils.
Swansea boss Russell Martin felt compelled to change a winning side after their success at Watford - with the relentless schedule in mind - with Darling, Joel Latibeaudiere, Luke Cundle and Cooper replacing Matthew Sorinola, Kyle Naughton, Olivier Ntcham and Michael Obafemi.