New Bristol City manager Derek McInnes will have to wait for his first victory in charge of the club following defeat to Birmingham City at Ashton Gate.
A 36th minute strike from Chris Burke opened the scoring for Chris Hughton's men.
The winger found space inside the penalty area to head Keith Fahey's cross past former England international David James in goal.
Hosting City rallied after the break, with both Neil Kilkenny and Nicky Maynard forcing Boaz Myhill into saves.
However, they were unable to force an equalising goal and were punished in stoppage time when Chris Burke added another goal deep into stoppage time.