Daniel Cousin scored on his first start for a month as Rangers eased past a spirited Gretna in the SPL at Ibrox.
Naismith put Rangers on easy street with the second goal
Cousin - set to discover whether Fifa will sanction his £3m move to Fulham this week - outpaced the Gretna defence to score after 12 minutes.
Steven Naismith doubled the advantage ten minutes later with a neat volley from Barry Ferguson's corner.
Chris Burke sealed victory on the hour before Kenny Deuchar headed a double either side of Kris Boyd's late fourth.
Cousin wasted no time in making an impact on his return to the starting line-up.
He pounced on a Ferguson header after 12 minutes, raced free of the Gretna defence and cooly rounded goalkeeper Greg Fleming to give Rangers an early lead.
Ten minutes later, Ferguson's corner found Naismith unmarked in the box and he spun and volleyed home from close-range.
With a comfortable two-goal cushion established so early Rangers took their foot off the gas and Gretna almost hit back.
Allan McGregor was forced to dive low to his left to smother a free-kick from Nicky Deverdics from the edge of the area.
John Paul Kissock then released Brendan McGill down the right flank and his cross was met by Paul Murray, whose flashing header came off McGregor's right hand post.
Despite the deficit the bottom-placed strugglers started the second half in sprightly fashion and enjoyed more possession.
Deuchar sent a header just wide from a McGill cross following patient build-up play involving the lively Kissock.
But just when Gretna appeared to be fighting their way back into the match, they were hit by a sucker punch.
A typically powerful run from Jean-Claude Darcheville saw the Frenchman surge down the left wing and into the Gretna box.
Burke latched on to his flicked cut-back, stepped inside a defender and sent a left-foot shot high past Fleming.
The game went flat again as the third goal appeared to knock the stuffing out of Gretna's mini-revival.
But Deuchar grabbed a deserved consolation goal after 71 minutes when he rose above the Rangers defence to head Mickael Buscher's corner low past a stranded McGregor.
Substitute Boyd put the icing on the cake with two minutes to go when he collected Steve Davis' precise through ball, rounded the keeper and slotted the ball into the empty net.
Rangers were beginning to look jaded after their midweek Uefa Cup exertions against Panathinaikos.
And Deuchar again took advantage of a static home defence to head a second goal for Gretna as the game wound to a close.
Rangers: McGregor, Broadfoot, Cuellar, Weir, Whittaker, Burke, Davis, Ferguson, Naismith, Darcheville (Novo 61), Cousin (Boyd 61). Subs Not Used: Alexander, Dailly, Faye, Furman, Fleck.
Goals: Cousin 13, Naismith 22, Burke 60, Boyd 88.
Gretna: Fleming, Barr, Hall, Meynell, Naughton, McGill, Murray (Wilkinson 70), Skelton, Deverdics (Baldacchino 77), Deuchar, Kissock (Buscher 70). Subs Not Used: Krysiak, Makinwa, Schultz-Eklund, Griffiths.
Goals: Deuchar 71, 89.
Ref: C Murray (Scotland).