Rangers manager Walter Smith gave Kris Boyd a place in the starting line-up at his old stamping ground in partnership with Jean-Claude Darcheville, while counterpart Jim Jefferies was able to name a more familiar side with Gary Locke, Allan Johnston and Mehdi Taouil all available.
Darcheville should have given the league leaders the perfect start inside two minutes when his excellent headed touch took him clear of the defence, but his attempted chip flew over the bar.
Kilmarnock were retaining possession much more effectively than in recent weeks and were much more like the side who finished fifth in the last two seasons.
A brilliant burst from Craig Bryson in the 11th minute took him past Barry Ferguson and Kirk Broadfoot, but his measured shot curled a foot wide of the post.
The league leaders went in front in the 25th minute thanks to Carlos Cuellar.
Ferguson flicked on Broadfoot's cross to the Spaniard who, from a suspiciously offside position, looped his header over Alan Combe and into the far corner.
Darcheville passed up another golden chance just before the interval when he easily beat Simon Ford, but again failed to hit the target under no pressure as he dragged his shot wide.
Boyd twice went close in quick-fire fashion six minutes into the second half.
First his glanced header slid past the upright, before he hit a 30-yard free-kick low to Combe's right but the keeper got down well to turn the ball behind.
The match turned on two incidents around the hour mark.
Johnston looked to have equalised for Killie when his rifled shot beat Allan McGregor, but Sasa Papac popped up on the line to brilliantly head the ball over his own bar.
Then a minute later, Jamie Hamill conceded a soft penalty when he handled the ball when challenging Boyd and the former Killie striker smashed the ball home to double the lead.
Broadfoot's error almost gave Kilmarnock a lifeline six minutes from time when he was short with a back-pass, but David Fernandez was forced wide by McGregor and couldn't hit the target from an acute angle.