The Light Blues keeper produced two outstanding saves in the first half of the match at Stair Park to keep his side in front of a plucky Stranraer side.
The 2-0 win meant they stayed 21 points ahead of their nearest rivals Dunfermline in SPFL League One and on course to wrap up the title next month.
Ally McCoist's men can complete the second stage of the "The Journey" with a victory over the second-placed side in the third tier at Ibrox on March 15.
Until Saturday, when they were held to a 3-3 draw by Stenhousemuir at home, Rangers had only dropped points in the league to Stranraer this season.
They were held to a 1-1 draw by them at Ibrox on Boxing Day when Jamie Longworth netted in the fifth minute of injury-time at the end of the match.
The Glasgow club found it hard going once more against the Wigtownshire men and were highly fortunate to return home with all three points.
A Lee Wallace strike - scored in the fourth minute of an occasionally bad- tempered encounter - and a late Jon Daly goal was all that separated them from their opponents at the end of the 90 minutes.
McCoist showed just how unhappy he was with the level of performance from his side at the weekend by making four changes to the starting line-up.
In the defence, Richard Foster took over from Sebastien Faure at right back while Bilel Mohsni replaced Emilson Cribari at centre half.
Admittedly, Faure was injured - he had been stretchered off and taken to hospital against Stenhousemuir - and Mohsni was returning from a two game suspension.
But David Templeton and Andy Little being replaced by Stevie Smith and Arnold Peralta respectively was clearly done in an attempt to bring about an improved display.
McCoist opted for a 4-2-3-1 formation with Ian Black and Peralta operating as deep-lying central midfielders, with Nicky Law pushing forward ahead of them.
Smith played on the left-hand side of midfield just ahead of Wallace while winger Fraser Aird took up his usual position on the right flank.
Rangers took the lead in after Law and Wallace played a neat one-two on the edge of their opponents' penalty box. Wallace let rip with a low left-foot shot and although Stranraer keeper David Mitchell managed to get a hand to it, the ball ended up in the back of the net.
The home team very nearly got back on level terms just two minutes later when Andrew Stirling played a free kick into a cluster of bodies in the Rangers area.
Daly stuck out a leg in an attempt to clear the danger. However, the burly striker only succeeded in diverting the ball towards his own net.
Bell did brilliantly to dive and push the ball past his left post for a corner.
Stranraer could not take advantage of the set-piece after that near thing.
Rangers suffered another scare shortly after that when captain Lee McCulloch went to ground due to an injury he sustained to his left foot.
The fact the defender was clutching his face as he lay on the Stair Park turf suggested the knock was a serious one and Cribari was ordered to warm up by McCoist.
But after receiving treatment from Rangers medical staff and walking it off McCulloch continued and Brazilian defender Cribari returned to the substitutes' bench.
Daly should have done far better with a header in the 18th minute after Smith set him up with a high ball upfield.
Despite not being under any pressure, his effort went well wide.
Bell came to the rescue of his side for the second time in the game in 34 minutes after a well-worked attacking manoeuvre by the host team.
Robertson volleyed a Mark Docherty knockdown at goal, and the Rangers goalkeeper had to stretch to his fullest to prevent the attempt going in.
Peralta riled the home supporters with a couple of physical challenges on Stranraer players in the first half and was fortunate not to find his name taken by referee Euan Anderson.
Stranraer defender Robertson was yellow-carded by the match official in the 53rd minute for hauling down Law when he was advancing towards goal.
McCoist's men were unfortunate not to build on their lead on the hour mark after producing the best move of the match.
Mohsni sent Wallace racing away down the left wing with a beautifully-weighted pass and the defender then whipped a cross in to the six-yard box.
Daly connected well with a powerful downward header only for the ball to get tangled up on the line in the outstretched legs of keeper Mitchell.
Peralta was finally booked for a late tackle on Grant Gallagher and was substituted shortly afterwards. Robbie Crawford took over from the Honduran.
Daly put a gloss on the result in the 88th minute when Mitchell failed to deal with a Foster long ball. He stroked the ball into an empty net.