Ronald de Boer turned in a sparkling performance as Rangers cruised to an easy victory.
The Dutchman, who often appears disinterested, looked fully focused as he scored with two clinical finishes.
An early goal by Peter Lovenkrands added to de Boer's goals and fully reflected the gulf between these two Glasgow sides.
Thistle stuck manfully to their task but were never able to match a Rangers side who did not have to move out of third gear to gain their victory.
The visitors were stunned by an early setback when Shota Arveladze controlled a Barry Ferguson free-kick before unleashing a powerful left-foot shot that keeper Kenny Arthur did well to block, only to leave Lovenkrands with a simple chance from close range.
Thistle nearly drew level when Jamie Mitchell sprung the home side's offside trap, but Stefan Klos raced from his line to block the striker's shot.
The home team increased their lead with a spectacular goal by de Boer.
Maurice Ross' long throw-in on the left somehow found its way through a maze of players to the Dutchman who, with his back to goal, hitch-kicked his shot high into the net.
De Boer was spraying superb passes all over the pitch but Arveladze squandered two good chances that had been created by the Dutchman.
De Boer looked to have scored another goal, but this time his effort was deflected into the side-netting before Arveladze stepped inside David Lilley only to see his well-struck shot covered by Arthur.
Rangers looked to finish the game off early in the second period with a third goal and nearly did so when Mikel Arteta's 30-yard curling free-kick was just touched round his post by the sprawling Arthur.
Lovenkrands headed a Kevin Muscat cross over from no more than six yards before de Boer stepped in to finish the match as a contest.
The Dutch striker was perfectly positioned to guide home a Lovenkrands cross after Arteta's well-weighted pass had released the Danish winger.
There was time for Rangers boss Alex McLeish to send on Michael Mols to a wonderful reception from the home fans, but his flick from a de Boer pass lacked power and Arthur gathered easily as Rangers saw out time