Boro’s Riley McGree scored the only goal of the game in the 25th minute when he converted Ryan Giles’ low cross.
Sunderland suffered a big injury blow before the match as top scorer Ross Stewart was forced to withdraw from the starting XI due to an injury.
The Black Cats will now prepare for Saturday’s home game against Millwall.
Our chief Sunderland writer Phil Smith has dished out his player ratings from the Riverside Stadium:
1. Anthony Patterson - 6
Little he could really do about the goal and made a couple of smart stops in the second half. 6 Photo: Martin Swinney
2. Lynden Gooch - 5
Had a tough brief up against Giles and couldn’t stop the cross for the opener. Made a couple of good runs forward but didn’t amount to much in the end. 5 Photo: Frank Reid
3. Luke O’Nien - 5
Did well in the air and stepped out when he could, but it was too easy for Boro to get in between him and Batth for the opener. 5 Photo: Frank Reid
4. Danny Batth - 5
Had a steady game and battled well against the hugely impressive Muniz, but will feel he and O’Nien could have done better for the goal. 5 Photo: Frank Reid