The Black Cats took a first-half lead when Luke O’Nien converted a rebound following Daniel Ballard’s header from a corner.
Sunderland then came under pressure in the second half, with goalkeeper Anthony Patterson saving an Ilias Chair penalty in the 62nd minute.
The visitors then secured the points eight minutes from time when Jack Clarke cut in from the left and scored with a low finish.
Clarke then added a third in stoppage-time following Dan Neil’s cutback.
Here’s how Phil Smith rated the Sunderland players:
1. Anthony Patterson - 9
An outrageous penalty save with his side’s lead still slender. Was little wrong with the penalty but it was a brilliant block. Commanded his box superbly, too. 9 Photo: Martin Swinney
2. Trai Hume - 7
Made a couple of uncharacteristically poor decisions on the ball in the second half but was excellent in the first and once again won just about everything that came within five yards of him. 7 Photo: Frank Reid
3. Daniel Ballard - 6
Did well in his battle with Chris Martin, erring only once or twice. Another clean sheet under his belt. 6 Photo: Frank Reid
4. Danny Batth - 7
Another steady performance from the impressive defender. Job done, again. 7 Photo: Frank Reid