Skipper James Tavernier scored two penalties and missed another as Rangers overcame Ladbrokes Premiership bottom side St Mirren 4-0 at Ibrox.
The Light Blues defender got the home side off the mark in the third minute then struck the post with his next effort from 12 yards, a decision disputed vehemently by the visitors, before grabbing his second early in the second half.
Striker Jermain Defoe made it 3-0 in the 79th minute, also from the spot, before Ryan Kent added a fourth two minutes later.
Steven Gerrard's side moved to within three points of leaders Celtic, although Brendan Rodgers' men can restore their six-point lead against St Johnstone at McDiarmid Park on Sunday as the title race keeps going.
As expected, Gerrard ran the changes from the William Hill Scottish Cup win over Cowdenbeath in midweek, with only new signings Steve Davis and Defoe and Nikola Katic keeping their places.
Saints, who had lost their previous four league games, made one change, with defender Anton Ferdinand in for Kyle McAllister while recent signings Mateo Muzek, Laurentiu Corbu and Dukens Nazon were on the bench.
The visitors got off to the worst possible start by conceding a penalty with less than two minutes played, defender Ethan Erhahon clumsily tripping Defoe inside the box to leave referee Andrew Dallas little option but to point to the spot.
Tavernier sent Buddies keeper Vaclav Hladky the wrong way with his penalty which should have been the catalyst for the Light Blues to surge on. However, it all went rather flat.
Rangers' second and more controversial penalty in the 23rd minute was again for a challenge on Defoe, this time by right-back Paul McGinn. And after lengthy protests from the Buddies players, for which defender Jack Baird was booked, Tavernier struck the outside of the post with his shot as Hladky dived the other way.
Kent clipped the top of the bar in the 35th minute with a curling shot from the edge of the box before Hladky saved a Defoe header from a terrific Katic cross.
The third penalty came in the 55th minute when Tavernier's cross was adjudged to have been handled by Greg Tansey, this time the Ibrox right-back blasting the ball down the middle.
Immediately, Nazon, on loan from Sint-Truiden, came on for Simeon Jackson to make his debut before Gers winger Daniel Candeias replaced Davis.
Rangers slowly cranked up the pressure and Hladky blocked a close-range shot from Defoe and then Morelos' effort on the rebound was blocked on the line by Ferdinand.
Muzek, on loan from Shakhter Karagandy, came on for Erhahon in the 72nd minute to make his St Mirren debut as did Romanian full-back Corbu, on for Paul McGinn.
In between those two substitutions, Hladky made good saves from Morelos and Candeias as Rangers pushed for a third which came through yet another penalty when Candeias was hauled to the ground at the edge of the box by Tansey, with Defoe blasting past Hladky before setting up Kent to dink the ball over the Saints keeper for number four.