Danny Wilson and Kenny Miller were also on the scoresheet as the Scottish champions secured an emphatic 4-1 win over Hearts, with Suso Santana the goalscorer for the Jambos.
The win allowed Rangers to move within potentially four games of retaining the championship.
Rangers made five changes from the side that crashed out of the Active Nation Scottish Cup midweek for the clash against Hearts, with Kris Boyd and Miller back in the side for the visit to Tynecastle.
Steven Davis recovered from illness and Lee McCulloch and Kevin Thomson both returned from suspension to bolster the midfield after sitting out Wednesday's defeat to Dundee United.
Hearts made three changes after defeating Edinburgh rivals Hibernian last week, and were boosted by the return of skipper Marius Zaliukas after a month on the sidelines, but Andrew Driver missed out through injury.
Jamie MacDonald replaced Janos Balogh in goal, with the latter absent from the squad, while Suso was also drafted into the starting line-up.
Rangers enjoyed a dream start to the game when they stunned Hearts by surging into the lead with just four minutes on the clock.
Boyd won a free-kick 30 yards out and Thomson stepped up to pick out Wilson at the back post and the youngster beat Ruben Palazuelos to the ball to bullet a header past MacDonald and claim his first goal for the Scottish champions.
Gary Glen had the ball in the back of the net for Hearts a few minutes later but was correctly flagged for offside, before drawing a decent block from Rangers goalkeeper Allan McGregor with a well-struck shot.
The home side were back on level terms after 16 minutes when Sasa Papac's disastrous attempt to clear a Zaliukas ball fell for Suso and he unleashed a superb, unstoppable volley past the helpless McGregor.
MacDonald was called into action at the other end when Davis tried his luck with a ferocious shot that the full-stretch Jambos goalkeeper just managed to tip over with Rangers failing to capitalise on the corner.
The Ibrox side continued to press but MacDonald was proving to be on fine form, racing off his line to deny Boyd before he had a chance to pull the trigger, before swiping a Miller effort over the crossbar.
But he was plucking the ball out of the back of the net after 31 minutes. Naismith rattled the crossbar before the ball broke again for Miller and this time he managed to deliver with a diving header past the keeper.
Hearts' hopes of another comeback in the second half were dealt a blow when Rangers extended their lead four minutes after the restart.
Naismith timed his run well to collect a Steven Whittaker pass before flicking into the bottom corner to claim his first goal since late September.
Hearts could have hit back quickly through David Obua but he screwed his shot wide, before McGregor did well to push a stinging shot from Zaliukas just over.
Boyd, still searching for his 100th SPL goal for Rangers, managed to force the ball home but the assistant referee already had his flag raised.
The celebrations began for the travelling fans with 77 minutes gone when Naismith struck again to grab his second goal of the day.
The midfielder was tripped 30 yards out before throwing himself in front of Davis' free-kick in plenty of space to glance a header past MacDonald and wrap up the three points for Walter Smith's men.