John Robertson started his reign as Livingston boss with a defeat as his side were swept aside by Kilmarnock.
Danny Invincibile (left) sealed the points for Killie
Steve Hislop gave Livi a surprise lead against the run of play when he headed in at the far post.
Gary Wales equalised with a fine shot on the turn, before Steven Naismith added a second with a crisp drive.
A second-half strike from Danny Invincibile wrapped up the points for Jim Jefferies' side, who remain firmly on course for a top-six finish.
Former Hearts boss Robertson, who this week succeeded Paul Lambert, spent four successful years at Almondvale as a coach but now faces a huge task to haul the Lions to safety.
Killie went into the match with just one defeat in eight SPL games and their confidence was clear to see from the start, Naismith turning cleverly on the edge of the box after two minutes and testing Ludovic Roy with a low drive.
The Lions had a lucky escape in the 12th minute when Invincibile's shot struck the right-hand post and when Naismith pounced on the rebound, Roy denied him with a magnificent save.
Livi took the lead with their first foray into the Killie half, Graeme Smith allowing a header from Hislop to escape his grasp, after the striker got on the end of a fine Paul Tierney free-kick.
In the 19th minute, the visitors went close to adding to their lead when Derek Adams headed inches over following another inviting Tierney centre.
Wales continued his impressive recent scoring run to level the scores shortly after, when he converted Naismith's knock-down.
Five minutes later, Killie took the lead when Naismith cut inside from the left of the box to fire low past Roy and into the right-hand corner of the Livi net.
It took until the 10th minute of the second period for either side to pose any kind of threat and it was Livi who were the first to show any intent, Sam Morrow's clean strike flying just wide of the post.
That seemed to liven Jefferies' men up and, after Wales had won the ball in midfield, he set Invincibile free down the right with a terrific pass.
The Australian hammered the ball past Roy to give the home side a two-goal cushion.
Kilmarnock: Smith, Wilson, Ford, Wright, Hay, Fowler, Johnston, Wales (Di Giacomo 87), Invincibile, Nish (Locke 85), Naismith (Murray 87). Subs Not Used: Bell, Lilley, Campbell, Adams.
Booked: Wilson, Naismith.
Goals: Wales 22, Naismith 27, Invincibile 59.
Livingston: Roy, Tierney (Hoolahan 61), Pinxten, Dorado, Mackay, Brittain (Walker 45), Adams, Vincze, Dair, Morrow, Hislop (Snodgrass 45). Subs Not Used: Woods, Strong, Weir, Miller.
Goals: Hislop 14.
Ref: C Murray