Attendance 50,301
Manager Walter Smith made five changes from Forfar with Kirk Broadfoot, Steve Davis, Pedro Mendes, Barry Ferguson and John Fleck replacing Steven Whittaker, Steven Naismith, Lee McCulloch, Maurice Edu and DaMarcus Beasley.
It was all Rangers in the opening stages - yet when the opening goal arrived in sixteen minutes it was the visitors who stunned the capacity crowd in their first attack when Jamie Hammill tapped the ball home from close range following a Garry Hay cutback.
The Light Blues were level just before the half-hour when a Mendes corner to the back post was headed downwards by Madjid Bougherra for Kris Boyd to volley home.
Sixty seconds later Rangers might have taken the lead when Sasa Papac headed a Davis cross over the bar when he might have done better.
It scarcely mattered however - for when Boyd's lay-off broke to Kenny Miller in 32 minutes he raced through to net the second goal.
The Ibrox men were rampant - two minutes later Mendes released Miller who beat Killie's offside trap to slide home goal number three.
It was Miller's second double in successive games. The game was as good as over - and the crowd could all have gone home there and then...
Another Mendes corner caused havoc in the visitors' defence in 39 minutes when visiting goalkeeper Alan Combe dropped the ball for Papac to stab goalwards only for Simon Ford to clear off the line.
Rangers were well in command at the interval - although the Ayrshire men did test McGregor in 54 minutes when Hammill saw his 25-yard shot held by the Ibrox goalie.
Nine minutes later a classic piece of skill from Mendes saw him cut in from the left before sending in an angled drive that was beaten away by Combe.
Aaron replaced Fleck midway through the second-half and immediately injected some liveliness into a 'Gers side that had dropped down a couple of gears.
Davis was inches away from connecting with a Miller cross in seventy minutes - then six minutes later Kyle Lafferty substituted for Boyd.
The home side were going through the motions, clearly believing the game to be won, yet might have conceded a second goal in 85 minutes when Manuel Pascali was through on a Mehdi Taouil slip only to see McGregor block his effort.
Four minutes later Miller should have completed his hat-trick when he broke on a Davis pass only to see his shot blocked.
Rangers were home and dry - and afterwards Walter Smith enthused:
"We're delighted to win. They scored with their first attack - but we reacted well.In the first-half especially Pedro Mendes and Barry Ferguson played particularly well."
RANGERS McGregor; Broadfoot, Weir, Bougherra, Papac; Davis, Mendes, Ferguson, Fleck (Aaron 67); Boyd (Lafferty 76), Miller
UNUSED SUBS Whittaker, Alexander, Edu, Naismith, Dailly
KILMARNOCK Combe; Murray, Lilley, Wright, Ford, Hay (Gibson 81); Hammill, Pascali, Skelton (Taouil 70); Bryson, Kyle
UNUSED SUBS Rascle, Sammon, Anson, O'Leary, Flannigan
REFEREE Brian Winter