St Mirren turned up the heat on seventh-placed Kilmarnock in the battle to finish as the highest-placed bottom-six Scottish Premier League side.
Paul McGowan played a one-two with Steven Thompson before firing past Killie keeper Cammy Bell early on.
Thompson volleyed St Mirren's second as half-time approached.
Kilmarnock's Dean Shiels had a penalty saved in the second half and the visitors held on to their lead to move to within a point of the hosts.
The Buddies currently boast a better goal difference than the Ayrshire men, while Aberdeen remain in contention with two rounds of fixtures to play, the Dons sitting three points behind St Mirren.
McGowan was the architect and scorer of the opening goal as he worked his way into the box from deep, linked with Thompson on the way, and forced the ball past Bell on nine minutes.
s Fowler on the rebound.
The hosts tried to respond and St Mirren stopper Craig Samson made saves in quick succession to deny Gary Harkins and then Jame
But the Buddies were not content to sit on their lead and Nigel Hasselbaink had two efforts saved and another off target.
Dieter Van Tornhout drew a save from Samson and Liam Kelly fired over as Killie tried to level, but the home side were undone on the stroke of half-time as Thompson struck.
Jeroen Tesselaar cantered down the left and crossed for Thompson to direct a superb left-foot shot into the net.
Kenny McLean came close to a third for St Mirren with a shot wide of the mark a few minutes into the second half.
A handball by Darren McGregor gave the home side a chance to pull one back from the spot but Shiels' effort was blocked by the feet of Samson, who blocked another shot by Van Tornhout in Killie's next attack.
Manager Kenny Shiels used all his substitutions at once in an attempt to change Kilmarnock's fortunes but the introduction of James Dayton, Matthew Kennedy and William Gros did not have the desired impact.
And the visitors could have added to their lead but McGowan was denied by Bell.