Saints were beaten at Ibrox as an Aballdah Sima double gave Rangers a 2-0 win in the cinch Premiership.
The Buddies had their chances in the first-half, but fell behind to a Sima on the final minute of normal time at the end of the half. And the Rangers forward added his and Rangers' second with 20 minutes remaining to ensure Saints left Govan empty-handed.
There were four changes from the side that lost at Ross County on Tuesday night. Richard Taylor, Ryan Flynn, Caolan Boyd-Munce and Jonah Ayunga came in for Charles Dunne, Keanu Baccus, Alex Greive and Mikael Mandron.
The Buddies started fairly brightly with Conor McMenamin curling a dangerous low ball in from the right. Ayunga couldn't get the touch on it that would have surely taken it beyond Rangers goalkeeper Jack Butland who managed to gather in the end.
The hosts had a good opportunity on 19 minutes when a ball swung to the back post met James Tavernier who nodded back across goal for Todd Cantwell. The Rangers midfielder had space but sclaffed his shot. Sima came close five minutes later when he headed a Tavernier cross over the bar.
Saints' best chance of the half came on 37 minutes when Boyd-Munce was within a whisker of putting the Buddies ahead. The midfielder's low curling effort from the edge of the box looked destined for the bottom left-hand corner but was tipped wide in what was a terrific save from Butland.
Caolan Boyd-Munce came close to an opener for Saints but was denied by a great save from Jack Butland (Image: Allan Picken)
The home side took the lead in the final minute of normal time at the end of the first-half. Sima lashed beyond Zach Hemming, who could do nothing to prevent it, from 12 yards to put the hosts ahead as we headed into the break.
Saints started brightly at the second-half in search of an equaliser and Butland made another good save to deny Saints a few minutes after the restart. This time it was Ayunga who had a go from range and the Rangers goalkeeper had to scurry across at full-stretch to turn the effort behind.
It was then Hemming's turn to be called into action on 53 minutes when he had to beat away a strike from Rangers captain Tavernier on the edge of the area. The Saints stopper got two strong hands behind it to push away.
Saints were still probing and got another opportunity on the hour mark when a Greg Kiltie pass got through the legs of Leon Balogun and fell for Ayunga on the edge of the area. The forward wasn't expecting it but managed to compose himself before getting a tame shot away that was gathered with relative ease by Butland.
Rangers doubled their advantage with 20 minutes of the match remaining. Cantwell's through pass found Sima in the clear and he used his pace to race through before slotting beyond Hemming to make it 2-0 and secure all the points for the home side.
Full-Time: Rangers 2-0 St Mirren
St Mirren: Hemming, Fraser, Gogic, Taylor (Dunne 72), Flynn, Boyd-Munce (Baccus 78), Tanser, McMenamin (Jamieson 78), Ayunga (Olusanya 72), Kiltie (Greive 78)
Subs Not Used: Urminsky, Bolton, Small, Mandron
Rangers: Butland, Tavernier (Tavernier 85), Goldson, Balogun, Barisic (Yilmaz 80), Lundstram, McCausland (Matondo 80), Cantwell (Lammers 85), Lawrence, Sima, Dessers (Danilo 62)
Subs Not Used: McCrorie, Souttar, Cifuentes, Davies
Referee: Matthew MacDermid
Assistant Referee: Graeme Stewart
Assistant Referee: David Dunne
Fourth Official: Peter Stuart
VAR: John Beaton
Attendance: 47,835
