Defender Dennis Cirkin scored the only goal of the game after converting the rebound from Alex Pritchard’s low free-kick, which was tipped onto the post by goalkeeper Ryan Allsop.
After dominating possession for most of the match, Sunderland then came under pressure in the second half but managed to see out the win.
Here’s how Phil Smith rated the Black Cats players against Cardiff:
1. Anthony Patterson - 7
Didn’t have many saves to make but defended his box really well against a direct opponent. 7 Photo: Martin Swinney
2. Lynden Gooch - 7
Excellent in the first half, thriving in the wing back role he enjoyed earlier in the season. Cardiff put him under more pressure in the second half but he dug in and got through. Energy and tenacity excellent. 7 Photo: Frank Reid
3. Trai Hume - 8
Smart move from Mowbray to move him into the heart of defence against a physical front two. Won so many of his headers and swept up well, an excellent display. 8 Photo: Frank Reid
4. Danny Batth - 8
Headed countless balls away and though it got a little nervy late on, he fully deserved his clean sheet. 8 Photo: Frank Reid