St Mirren defeated Rangers at Ibrox for the first time since 1991 as goals from Mikael Mandron and Toyosi Olusanya saw the Buddies deservedly win 2-0 in Govan.
A strong first-half performance saw Saints go in level at the break and they got their rewards in the second 45 when Mandron and Olusanya struck to ensure a famous win on the third anniversary of manager Stephen Robinson's appointment.
There was one change to the side that drew with Hibernian last weekend as Jonah Ayunga came in for Toyosi Olusanya. And it was the Kenyan forward who was presented with a brilliant early opportunity to put Saints ahead with just eight minutes on the clock. Jack Butland sent a low clearance straight to the feet of the Ayunga. He took a touch before his powerful strike was pushed away by the Rangers goalkeeper who got two strong hands behind it. The rebound fell to Mikael Mandron who took it first time with Butland tipping over.
Rangers forced a saved from Zach Hemming a few minutes later when Vaclav Cerny got a shot away, but it was straight at the stopper.
Some loose play in the Saints defence saw Rangers steal the ball around 25 yards from goal with Hamza Igamane firing over. The Rangers forward was shown a straight red card as the game approached half-time when he went in hard on Saints skipper Mark O'Hara. But referee Kevin Clancy was advised to have a look at the incident again on the pitchside monitor by the VAR and he downgraded to a yellow.
The Buddies started the second-half with the same intent that they showed in the first. Caolan Boyd-Munce was inches away from seeing his cross sneak into the top corner of the net on 48 minutes.
And the Saints' would hit the front just three minutes later when Mandron fired home. Hemming launched it forward, Ayunga won his header to send Mandron clear and he blasted beyond Butland. It was initially disallowed as the referee believed the striker had fouled Clinton Nsiala but a long VAR check showed the 'Gers defender had clipped his own heels and the goal was given.
That sparked Rangers into some action with Nicolas Raskin seeing a long-range effort pushed away by Hemming just before the hour mark before Cerny drilled a powerful strike wide four minutes later.
Stephen Robinson made a triple change on 65 minutes and one of the subs, Olusanya, would send Saints into dreamland when he doubled our advantage. Killian Phillips flipped the ball over the top and Olusanya outmuscled Nsiala to strike beyond Butland to make it 2-0.
Marcus Fraser was inches away from adding a third with a little over 10 minutes to go when he headed just over from a corner, but two would do as Saints completed our first back-to-back wins over the Light Blues since 1980.
Full-Time: Rangers 0-2 St Mirren
St Mirren: Hemming, Fraser, Gogic, Taylor, Alebiosu (Bwomono 65), Phillips (Kiltie 76), Boyd-Munce (Smyth 65), O'Hara (c), John (Tanser 90), Mandron, Ayunga (Olusanya 65)
Subs Not Used: Urminsky, Kenny, Idowu, Oseni
Rangers: Butland, Tavernier, Propper, Nsiala, Jefte, Diomande (Lawrence 72), Raskin, Cerny, Hagi (Bajrami 72), Igamane (Danilo 58), Dessers
Subs Not Used: Kelly, Yilmaz, Fernandes, McCausland, Rice, Curtis
Referee: Kevin Clancy
Assistant Referee: Graeme Stewart
Assistant Referee: Gordon Crawford
Fourth Official: Duncan Williams
Attendance: 49,994
