The win over the bottom side in the table moved Stewart Maxwell’s side five points clear of the Premiership relegation zone, with games in hand.
There was little between the sides in the opening period with both defences well on top.
Rob Roy were looking to bounce back after two successive league defeats.
But it was the visitors created the first chance in the 10th minute with home keeper Craig Gordon saving low from Alan Christie.
Then, at the other end, Lee Gallacher saw his shot from the edge of the box sail over the Rangers crossbar.
Five minutes later Gary Carroll had a low shot easily saved by Cambuslang’s keeper Blair Cousar and then, after a period of Rabs pressing, Gallacher sent a decent effort narrowly past the post.
The home side were denied on the half hour mark when Graeme Ramage’s shot was parried by Cousar and Martin McBride was on hand to head the ball home, only to be flagged offside by the assistant referee.
With the Roy looking for a half-time lead Lewis Kinnaird’s deep cross to the far post was spilled by Cousar but Carroll could only head the ball wide. Then McBride’s goal bound shot was scrambled clear as the teams went into the break still level.
However it took only two minutes of the second half for Rob Roy to make the breakthrough.
Alberto Vezza broke free down the right hand side and cut in to the penalty box before side footing a left-foot shot past Cousar.
Rabs then doubled the lead in the 53rd minute when clever outfield play from Vezza resulted in a perfect pass to Ramage who ran through on goal and dribbled past Cousar to slot the ball into the vacant net.
Cousar then made a good save from Vezza as the Rabs looked to increase their lead.
Nevertheless Cambuslang, to their credit, never gave up and Ryan Bennett tested Gordon from 20 yards.
At the other end substitute Willie Sawyers’ drive from the edge of the penalty box lacked power to trouble Cousar as the Roy continued to press for another goal.
In a Cambuslang counter attack Simon Marriott sent a Ryan Mackey cross past the post when in a good goal scoring position.
However with 10 minutes remaining substitute Joe Slattery put the game out of reach of the Lanarkshire side when he sent a brilliant 25-yard low drive in to the net giving Cousar no chance.
McBride went close with a free kick that went narrowly past the post before the Rangers pulled a goal back in the final minute, when substitute Kas Moloka took advantage of slack Rabs’ defending to blast the ball past Gordon from eight yards.
This Saturday Rabs travel to Troon for a match rearranged after being postponed earlier this month.
Troon are just one place below Rabs in the table. The sides drew 1-1 in their first meeting of the season at Guy’s Meadow in November.
Report: Neil Anderson