They opened the scoring as Amad Diallo wriggled away from three defenders before threading the ball through for Ellis Simms to clinically dispatch it past John Ruddy and into the bottom corner.
Scott Hogan then had a huge chance to equalise before half-time as he raced through on goal but Anthony Patterson spread himself to make the block.
Diallo doubled the lead shortly after the restart as he collected possession in the right channel and worked his way into the box before unleashing a brilliant curling effort into the far top corner.
Birmingham pulled one back in the 78th minute as Lukas Jutkiewicz finished well inside the box after Bailey Wright completely missed the ball from a cross.
Patterson saved the three points for the Black Cats as he made a terrific, point-black, block from Dion Sanderson’s powerful effort in the six-yard box.
Whilst Amad produced a goal and an assist out wide and Patterson made two huge saves, the real hero for Tony Mowbray’s side was central defender Danny Batth.
Sunderland were pinned in their own half for much of the second half as the home side pushed hard to get back into the game, and then equalise, after Diallo’s strike.
However, the Black Cats held strong until the end to secure all three points, and Batth’s heroic defending played a huge role in the victory.
The former Stoke City tank was in a perfect position more often than not as he made a game-high 11 clearances. This shows that he was in the right place at the right time to clear his lines, preventing Patterson from being called into action much outside of the two big saves that he did make.
Batth won 75% of his individual duels (six out of eight) as he was able to physically dominate the opposition forwards – despite playing against the tricky pairing of Troy Denney and Scott Hogan – and win the ball back for Sunderland on multiple occasions.
As per SofaScore, the central defender also made three blocks and two tackles, whilst not being dribbled past a single time throughout the 90 minutes.
The immense enforcer was, therefore, the real hero for Mowbray as he put his head and body where it hurt to keep Birmingham at bay time and again. He may not have scored a stunning goal or provided a beautiful assist but he did the dirty work that needed to be done for the team to win and that is why he deserves praise for his performance.