Despite a bright start, the Black Cats fell behind midway through the first half when Jamie Allen converted Viktor Gyokeres’ cutback.
Gyokeres eventually got on the scoresheet in the closing stages when he beat goalkeeper Anthony Patterson with a close-range finish, before Amad netted a late consolation goal in stoppage-time.
Mowbray’s side will now prepare for next weekend’s home game against Stoke.
Here’s how Phil Smith rated the Sunderland players at the CBS Arena:
1. Anthony Patterson - 6
Distribution was OK in the main under some pretty aggressive pressing. Nothing he could do about either goal and defended corners well. 6 Photo: Martin Swinney
2. Trai Hume - 5
Just a touch slack in his passing at times, though he did land a few of his trademark challenges. One of a few who just looks a bit leggy. 5 Photo: Frank Reid
3. Daniel Ballard - 6
For the most part did pretty well in his battle with the outstanding Viktor Gyokeres, winning a lot of his duels even if the striker did eventually get in front of him to score the second. 6 Photo: Frank Reid
4. Danny Batth - 6
Came within inches of giving his side an early lead but his effort hit the bar and bounced agonisingly clear. Pretty solid in the main and little he could do about either goal as Sunderland were exposed on the break. 6 Photo: Frank Reid