However, the Dons, who have played a game more than the Hoops, only secured the three points at Rugby Park after the home side missed an injury-time penalty.
Adam Rooney scored his 26th goal of the season for Aberdeen and although Craig Slater equalised, Cameron Smith scored what turned out to be the winning goal after 69 minutes.
The game might have had an altogether different outcome had Slater not seen his 90th-minute spot-kick saved by Scott Brown.
Aberdeen’s win means the title race continues, while the gap between Killie and the relegation play-off place remains a reasonably comfortable seven points.
Both sides wanted to be positive and demonstrated that willingness with an attack each in the game’s early exchanges, Kilmarnock forcing a corner and Aberdeen doing likewise with a puncturing Jonny Hayes run down the left wing, although both came to nothing.
Rooney glanced a header narrowly wide of the target and Smith forced Craig Samson into a reflex save to his left as the Dons started to crank up the pressure.
The game settled down into a lifeless affair during the second half of the first period of play but burst into life six minutes before the interval when the visitors broke the deadlock.
Rooney gave Aberdeen the lead from no more than a yard out in the 40th minute when he headed in Donervorn Daniels’ knock down from a free-kick and it was no less than they deserved at that stage of the game.
Kilmarnock, though, equalised through a beautiful Slater goal just two minutes after the restart.
The midfielder was given time and space to curl a dipping right-footed shot into the corner of the goal and put his side back on level terms, although it only seemed to inspire their opponents.
Hayes fired a shot across Samson which he did well to keep out and Smith then restored the Dons’ lead at the end of a swift counter-attack.
The striker met Niall McGinn’s cross at the front post with a firm header which gave Samson no chance.
Chris Johnston attempted to get Kilmarnock back in the game with a long-distance shot and the home side were given a late lifeline when goalkeeper Brown inexplicably clattered Lee Miller when competing for an aerial ball.
With the clock showing 90 minutes played, Slater stepped up to take the spot-kick but his effort was a tame one and was pushed away by Brown, diving to his left.