Matty James added the fourth in the 49th minute to compound the woes of City manager Derek McInnes, whose side slipped to the bottom of the table.
Cardiff missed a chance to increase their position on top of the table as the leaders were held to a 0-0 draw at home to Ipswich.
However, Malky Mackay's side are still eight points clear of Hull and 10 ahead of Leicester.
Crystal Palace squandered the opportunity to improve their promotion prospects after crashing to a late 1-0 defeat at Burnley.
Former West Ham forward Junior Stanislas marked his first start since November by curling a brilliant strike into the top corner with nine minutes to go and Palace dropped to fourth as a result.
Middlesbrough also suffered a setback in their promotion challenge as play-off hopefuls Watford won 2-1 at the Riverside Stadium.
Czech Republic striker Matej Vydra, on loan from Italian side Udinese, fired home in time first half stoppage-time and struck his second in the 83rd minute to ensure Watford consolidated their play-off place.
Australian forward Scott McDonald got one back for Middlesbrough in stoppage-time.
Millwall are two points outside the play-off places after a 1-1 draw at Bolton.
Andy Keogh converted a ninth minute penalty for Lions, but Keith Andrews levelled with a 34th minute spot-kick.
Elsewhere, Barnsley climbed off the bottom with a 2-0 win over Yorkshire rivals Leeds at Oakwell, while Alex McLeish secured his first win as Nottingham Forest manager, a 2-1 success against struggling Peterborough at the City Ground.
Brighton beat Derby 2-1, Charlton won 2-1 at home to managerless Blackpool and Huddersfield scored a late equaliser to deny Birmingham manager Lee Clark a win at his former club.
-AAP