Match ends, Morton 0, Rangers 2.
Rangers were reduced to 10 men against Morton but still restored their five-point lead at the Championship summit.
Kenny Miller took advantage of a deflection in the box to poke the visitors in front.
Morton gave a good account of themselves but could not score an equaliser, and Barrie McKay played a neat one-two before doubling the lead.
Andy Halliday was shown a second yellow card for celebrating his side's second goal in front of the Morton fans.
The decision riled Rangers' coaching staff, but the team saw out the win against a spirited Morton side.
From the outset, Morton's play was a blend of energy, vigour and intent.
The plot was to pressurise Rangers players, particularly when they took the ball over the halfway line. Both full-backs were also harried, and James Tavernier had an awkward night trying to cope with the lively and spirited Bobby Barr.
The visitors were never wholly comfortable at Cappielow. Even in possession, their passing lacked the tempo or precision that has underpinned so much of their progress this season.
Morton were well served in midfield by Joe Mckee, up front by Denny Johnstone and Declan McManus and at left-back by the sure-footed Mark Russell, who kept Martyn Waghorn unusually quiet. Yet Rangers still carved out some half chances.
Miller would have been frustrated by the way he skewed a header wide from a central position and from close range. Lee Wallace also sent a shot wide from a good position. It was in keeping with the nature of Rangers' performance that their goal came from a moment of luck.
When Halliday struck a shot from 20 yards out, the ball bounced off the chest of defender Thomas O'Ware and fell to Miller, who prodded it past Derek Gaston, the Morton goalkeeper.
The home side did not lose heart, though, and a driving run and cross by McManus caused some alarm for Rob Kiernan, although he managed to slide across to block out the danger. The home fans appealed for hand ball, but it was his leg that made contact.
Morton raised their tempo after the break, which caused anxiety in the Rangers defence as the game opened up. McManus was alert, shooting wide after Rangers conceded possession then seeing his effort saved by Wes Foderingham after Barr had skinned Tavernier on the left and crossed into the box.
Rangers responded by changing their side, with substitutions seeing McKay move into midfield. He grew in stature, striking the bar then embarking on a driving run, playing a one-two with Miller and expertly clipping a shot beyond Gaston's reach and into the net.
The visitors' celebrations were cut short, though, with Halliday shown a second yellow card for gesturing triumphantly to the Morton fans. That decision infuriated Rangers manager Mark Warburton, who was eventually spoken to by the referee Barry Cook.
The dismissal was a set-back, but the home side saw the game out.
- 16BarrSubstituted forScullionat 84'minutes
- 11McCluskeySubstituted forTidserat 78'minutesBooked at 83mins
- 9JohnstoneSubstituted forSamuelat 82'minutes
- 2TavernierBooked at 45mins
- 27WilsonBooked at 67mins
- 8ZelalemSubstituted forForresterat 58'minutes
- 16HallidayBooked at 72mins
- 7LawSubstituted forShielsat 59'minutes
- 9MillerSubstituted forBallat 75'minutes
- Barry Cook
- Shots on Target
Second Half ends, Morton 0, Rangers 2.
Attempt missed. Declan McManus (Morton) header from the centre of the box is high and wide to the left.
Corner, Morton. Conceded by James Tavernier.
Attempt missed. Declan McManus (Morton) right footed shot from outside the box misses to the right.
Attempt saved. Barrie McKay (Rangers) right footed shot from the centre of the box is saved in the bottom left corner.
Attempt blocked. Ross Forbes (Morton) right footed shot from outside the box is blocked.
Attempt missed. Martyn Waghorn (Rangers) left footed shot from the right side of the box is just a bit too high.
Corner, Morton. Conceded by Wes Foderingham.
Attempt saved. Declan McManus (Morton) right footed shot from outside the box is saved in the centre of the goal.
Attempt saved. Harry Forrester (Rangers) right footed shot from the left side of the box is saved in the top centre of the goal.
Attempt saved. Ross Forbes (Morton) left footed shot from outside the box is saved in the top centre of the goal.
Substitution, Morton. Jon Scullion replaces Bobby Barr.
Attempt missed. Declan McManus (Morton) right footed shot from outside the box misses to the left.
Michael Tidser (Morton) is shown the yellow card for a bad foul.
Substitution, Morton. Alex Samuel replaces Denny Johnstone.
Foul by Declan McManus (Morton).
Dean Shiels (Rangers) wins a free kick in the defensive half.
Corner, Morton. Conceded by Dominic Ball.
Attempt saved. Harry Forrester (Rangers) left footed shot from the centre of the box is saved in the top centre of the goal.