A Mark O'Hara brace wasn't enough for Saints to take anything at Ibrox as three late Rangers goals gave the hosts all three points.
O'Hara struck twice either side of half-time to bring us level, but two goals in two minutes from Alfredo Morelos in the final 10 minutes as well as a Scott Arfield finish gave Rangers the win.
Boss Stephen Robinson made two changes to the side that defeated Hearts 2-0 at Tynecastle last weekend. Keanu Baccus dropped out of the squad altogether with a niggling knee injury to be replaced by Greg Kiltie, while Scott Tanser started in place of Thierry Small.
Rangers were awarded a penalty kick with just four minutes on the clock. Alex Gogic was penalised for a trip on Nicolas Raskin and referee Steven McLean pointed to the spot. The Ibrox side had been awarded penalties in both their previous games with the Buddies this season with James Tavernier scoring on both occasions, but this time the Rangers captain was denied by a brilliant Trevor Carson save. The Saints stopper dived to his right to push away the effort and despite a check for a retake none was forthcoming.
Saints forced a succession of corners a couple of minutes later but nothing came of them other than a 20 yard effort from Greg Kiltie that went well over.
The home side were dominating the bulk of the possession and had their best chance on 26 minutes when Fashion Sakala managed to wriggle clear of Marcus Fraser and get his shot away, but Carson did well to beat away the effort. The hosts would take the lead a minute later though when Todd Cantwell knocked Tavernier's low ball from the right in off the bar. There was a VAR check for offside but the goal stood.
The Buddies passed up a brilliant opportunity to go level when Kiltie robbed Ben Davies of the ball and drove forward but the Saints midfielder couldn't pick out Curtis Main who would have been one-on-one with Allan McGregor. Saints had another decent chance three minutes later when Kiltie shot straight at McGregor from 20 yards.
Charles Dunne made a brilliant last-ditch challenge to deny Rangers a second with five minutes of the half remaining. The hosts had players queuing up at the back post to meet Sakala's low ball across from the right, but the Saints defender got in just ahead of those waiting to pull the trigger.
Saints drew level in first-half stoppage time when Mark O'Hara scored his 11th goal of the season with a stunning volley. The midfield man controlled Kiltie's cross and it sat up beautifully for him to lash a super strike into the top corner via the post.
Mark O'Hara celebrates in front of the away support after drawing us level at Ibrox (Image: Allan Picken)
Rangers retook the lead just three minutes after the restart when Sakala headed home a Borna Barisic free-kick. Carson was then called into action twice in the space of a few minutes when he punched away a Tavernier free-kick that was heading for the top corner before clawing away Raskin's 20 yard effort.
The manager made two changes on 63 minutes when he introduced Small and Alex Greive in place of Tanser and Tony Watt. Two minutes later Saints were level a second time and once again it was O'Hara who got the equaliser. Small fed the ball wide to Strain whose cross was deflected high into the air. The Rangers defence couldn't clear their lines and O'Hara was on hand to finish from just inside the Gers box to make it 2-2.
Rangers made a triple substitution as Glen Kamara, Ianis Hagi and Scott Arfield entered the fray on 77 minutes. And the changes gave the hosts added impetus with Morelos netting twice in quick succession to take the game away from Saints. Arfield then got himself on the end of a Cantwell pass on 86 minutes to end the afternoon.
Saints' top six hopes go to the final game before the split with Kilmarnock the visitors to the SMiSA Stadium next Saturday.
Full-Time: Rangers 5-2 St Mirren
St Mirren: Carson, Fraser, Shaughnessy (c), Dunne, Strain, Kiltie (Boyd-Munce 90), O'Hara, Gogic (Flynn 87), Tanser (Small 63), Watt (Greive 63), Main (Offord 87)
Subs Not Used: Urminsky, Gallagher, R. Taylor, Jamieson
Rangers: McGregor, Tavernier (King 89), Souttar, Davies (Kamara 77), Barisic, Lundstram, Raskin (Hagi 77), Cantwell, Sakala (Matondo 62), Tillman (Arfield 77), Morelos
Subs Not Used: McLaughlin, McCausland, Lyall, Rice
Referee: Steven McLean
Assistant Referee: Alan Mulvanny
Assistant Referee: David Dunne
Fourth Official: Alan Newlands
VAR: Andrew Dallas
Assistant VAR: Graeme Leslie
Attendance: 48,703
