First-half goals from Paul McGowan and Steven Thompson helped St Mirren to a 2-0 victory over Kilmarnock at Rugby Park.
McGowan opened the scoring after nine minutes when he charged forward and coolly slotted beyond Cammy Bell.
On the stroke of half-time Thompson doubled Saints' advantage, when he blasted home from Nigel Hasselbaink's cut-back
Kilmarnock were handed a lifeline 10 minutes into the second half when Darren McGregor was adjudged to have handled Dean Shiels' shot inside the area and Shiels stepped up to take the resulting penalty but was denied by Craig Samson.
The visitors took the lead after nine minutes with their first real chance of the match. Thompson had to be brave to win the ball on the halfway line and McGowan charged forward before coolly slotting the ball beyond Cammy Bell.
A wonderful piece of goalkeeping by Samson ensured Saints retained their lead when he somehow stopped Shiels' close-range effort after failing to hold Gary Harkins' fizzing drive.
On the stroke of half-time Thompson doubled Saints' advantage, when he blazed Hasselbaink's cut-back beyond Bell.
Kenny McLean sent an effort inches wide on after combining well with Hasselbaink before the hosts were handed a lifeline when Beaton pointed to the spot after McGregor was adjudged to have handled Shiels' shot.
The midfielder stepped up to take the resulting spot-kick but his poor effort was saved by the legs of Samson and with Kilmarnock throwing men forward, St Mirren looked to hit on the counter-attack and only a fingertip save by Bell prevented McGowan from adding his second on 63 minutes.
The hosts continued to search for a way back but rarely threatened, meaning St Mirren closed the gap on Kilmarnock to two points in the Clydesdale Bank Premier League table.