It looked set to be a frustrating evening for Derek McInnes' side as, after a rampant first-half, they couldn't quite breach Jacob Chapman's goal.
However, an inspired second-half substitution to introduce the North Macedonian proved vital as he latched onto a Ryan Naderi flick-on with time running out and dinked the ball over the advancing St. Mirren goalkeeper to deliver a massive three points for his side.
From the team which defeated Motherwell at the weekend, in came Ryan Naderi in the absence of Lawrence Shankland, alongside first starts for both Kevin Kelsy and Badredine Bouanani.
Kelsy made his debut for the club just four days ago in the win over the Steelmen, and he was immediately involved when his expert lay-off into Nico Raskin allowed the Belgian to feed Naderi into a dangerous shooting position before the German was thwarted by Jacob Chapman in the St. Mirren goals.
The visitors, who shipped five in Govan on Premier Sports Cup duty just last month, pieced together a decent move minutes later when former Gers defender, Declan John, advanced into the penalty area and clipped towards the back post where Calvin Ramsay scooped well over the crossbar.
However, few inside Ibrox could argue that the opening proceedings didn’t belong to Derek McInnes’ side.
Raskin was first to threaten when he drifted into space and glanced a Bouanani delivery goalwards, with Chapman reacting impressively to claw his header to safety.
A delicious slide rule pass from Djeidi Gassama soon tempted James Penrice into space on the left. The full-back’s cross was flashed wickedly across the face of goals where Naderi appeared set to tap home before a last-ditch intervention from the sliding Henry Fieldson.
Ramsay almost contrived to volley beyond his own goalkeeper on 19 minutes, and from the resulting corner Kelsy was inches away from marking his first start with a goal when he rose highest inside the penalty area and nodded goalwards, but Nikolas Agrafiotis hacked to safety on the goalline.
The Ibrox crowd were certainly enjoying the relentless attacking endeavour from those in blue, and they were almost brought to their feet when Chapman could only paw Gassama’s curling effort into the path of Bouanani, who cannoned his rebound against the midriff of the St. Mirren goalkeeper.
The stream of attacking towards the visiting goal stemmed somewhat before the interval – Kelsy nodding into the goalkeeper’s arms from 15 yards out aside – but it resumed minutes into the second period when Gassama squared up his marker in typical fashion but could only fire off target from distance.
Ramsay was perhaps fortunate to escape a booking when he hauled the Mauritanian international to the ground on the edge of the penalty area as he attempted to latch onto an early cross from Raskin.
Indeed, he was cautioned just minutes later for a similar offence on Bouanani.
As the hour mark approached, McInnes ought to have been scratching his head as to how his side weren’t ahead in the contest – and by a sizeable margin.
He turned to his substitutes bench and introduced both Minsu Kim and Findlay Curtis in place of Bouanani and Kelsy.
On 65 minutes, the hosts were incredibly grateful for Ivor Pandur – who had little to contend with until this point – when he produced a huge save to deny Fraser Taylor after the midfielder was released through on goal just inside the Rangers half and had only the Croatian goalkeeper to beat.
It was certainly a warning sign for McInnes’ men as the Paisley side looked buoyed by their newfound confidence in the second period.
Further reinforcements arrived from the bench as Cammy Devlin and Bojan Miovski entered the fray with just under a quarter of an hour remaining.
And with just minutes remaining - and the fourth official set to raise his board to announce any time added on - Miovski came up with the decisive moment.
He reacted first to Naderi's expert flick-on, steadying himself just in time to send a delicious lob over the advancing Chapman to spark scenes of jubilation inside Ibrox.
RANGERS: Pandur, Sterling, Fernandez, Makhanya, Penrice, Neil (Chukwuani, 82), Raskin (Devlin, 76), Bouanani (Minsu, 59), Gassama (Miovski, 76), Naderi, Kelsy (Curtis, 59)
Subs not used: Kelly, McCrorie, Godfrey, Dragojevic
ST. MIRREN: Chapman, Ramsay (Richardson, 61), Gogic, Jackson, John (De Barros, 90), Carr, Fieldson, Taylor, Mochrie (Thomas, 61), Kabia (Sule, 76), Agrafiotis (Young, 76)
Subs not used: Mullen, King, Farquhar, McEvoy