As a contest the match was over before 20 minutes elapsed with goals from Nacho Novo and a double by Kris Boyd.
Boyd then completed his hat-trick from the penalty spot before Kenny Miller scored the best goal of the half just before the interval with a 16-yard volley.
The home team went ahead early on when Boyd's 25-yard right-foot shot from a short free-kick was spilled by keeper Michael Fraser, allowing Novo the easiest of finishes from two yards.
It got worse for the visitors shortly after when Pedro Mendes' clever pass beat the offside trap and Miller unselfishly played the ball across to Boyd who rolled it into the empty net.
There were several other scares for a panicky Inverness defence before Rangers scored their third.
Grant Munro carelessly conceded possession to Mendes who immediately transferred the ball to Boyd and the striker made no mistake from the edge of the box.
Boyd claimed his hat-trick from the penalty spot after Miller was brought down in the box by Munro.
In a swift break for the home team, Mendes' flick pass found Boyd who laid the ball off to Miller but the striker shot over from ten yards.
Rangers made it five on the stroke of half-time with a superbly crafted goal. Madjid Bougherra's pass found Novo almost on the by-line and his cross was volleyed home by Miller over his shoulder with the keeper helpless.
The visitors must have been happy to hear the referee's whistle for half-time and in fairness to Thistle they could have had a couple of goals in the second half as Rangers switched off.
Allan McGregor made a superb save from Ian Black's 25-yard shot and also did well to block substitute Garry Wood's effort.
As well as going back to the top of the table, Rangers had the luxury of introducing skipper Barry Ferguson who had been absent through injury for four months and youngster Rory Loy for the last half-hour with the points already safely secured.