St Mirren defender Kirk Broadfoot gifted Kilmarnock three points as the visitors left Love Street with a deserved victory.
David Fernandez celebrates as Kirk Broadfoot tumbles into his own net
Although Killie had a slight first half edge, there was little attractive football on display for the fans.
Mediocre Saints were a shadow of the side who won at Hearts last week, and after 70 minutes their luck ran out.
David Fernandez fired a shot across the danger zone, and Broadfoot could only direct the ball into his own net.
St Mirren - fresh from last Saturday's shock victory at Tynecastle - made two changes.
Garry Brady and John Potter missed out through injury, so former Livingston midfielder Richard Brittain and Craig Molloy were drafted into the starting line-up.
Kilmarnock boss Jim Jefferies kept the same side, despite the disappointment of defeat at Dunfermline Athletic last week.
And the visitors set about Saints in positive fashion, commanding the early possession.
Killie's Gordon Greer attempted a sliced cross forcing Tony Bullock to tip the ball over his bar.
Danny Invincible was playing with verve for the visitors, and his cross saw Steven Naismith head just wide in the best opportunity for either team to break the deadlock.
However for all the competitiveness on display, both sides lacked a creative edge.
The Buddies were disappointing, as throughout the first half, Killie goalkeeper Graeme Smith was rarely troubled.
Although striker John Sutton was making his presence felt in Killie's box, there was a distinct lack of finesse from St Mirren.
The second half tempo increased with both sides anxious to spark into life.
But just when St Mirren were beginning to cause problems for Killie, the cruellest of fates befell Broadfoot.
Greer dispatched a tremendous 30-yard pass across Saints' defence, and David Fernandez managed to turn the ball back across goal, only for stopper Broadfoot to help the ball into his own net.
A Simon Lappin free-kick from 20 yards which was deflected just over the Killie bar was as close as the home side came to an equaliser.
But Jefferies' men hung on to secure the victory they merited.
St Mirren: Bullock, van Zanten, Broadfoot, Millen, McGowne (Mackay 84), Murray, Lappin, Sutton, Kean, Brittain (Corcoran 72), Molloy (Mehmet 84).
Subs Not Used: Smith, Maxwell, McKenna, Iain Anderson.
Booked: van Zanten, Murray.
Kilmarnock: Smith, Fowler, Hay, Greer, Naismith, Wales (Nish 72), Invincibile, Johnston, Frazer Wright, Grant Murray, Fernandez (Di Giacomo 90).
Subs Not Used: Harpur, Stephen Murray, Leven, Campbell, Adams.
Booked: Hay, Frazer Wright, Naismith.
Goals: Broadfoot 70 og.
Ref: C Murray