Seb Drozd wrote himself into Scottish Cup history by sinking Rangers with a stunning winner at Ibrox where Gers skipper James Tavernier had a last-gasp penalty saved by Calum Ferrie.
The famous old competition was Philippe Clement's side's last realistic chance for a domestic trophy this season as the Gers sit 13 points behind Premiership leaders Celtic, who beat them in the Premier Sports Cup final in December. The Light Blues are through to the last 16 of the Europa League.
Callum Davidson's Championship side kept a below-par home side at bay in the fifth-round tie before scoring the only goal in the 69th minute through substitute Drozd, the Englishman who signed last October from Millwall.
The home side were dramatically awarded a penalty in the fifth minute of added time when William Tizzard fouled Cyriel Dessers but Tavernier saw his spot-kick saved by Ferrie.
One of the greatest shocks in Scottish football history will put Clement back under the spotlight and the boos rang round Ibrox after a defeat which had been unthinkable before the game.
Davidson enjoyed cup success with St Johnstone at Ibrox in 2021 on their way to winning the trophy but few would have bet on a second success with the Spiders.
Liam Kelly took over from Jack Butland in goal for Rangers and 22-year-old Portuguese defender Rafael Fernandes, on loan from French side Lille, made his first start as did 18-year-old midfielder Bailey Rice. Robin Propper and Nedim Bajrami returned.
Adam Devine, on loan from Rangers, missed out for the visitors, replaced by 19-year-old Zach Mauchin. Drozd dropped to the bench in favour of Kyle Hurst, signed on loan from Doncaster.
The Light Blues made all the early running but their finishing was mostly sub-standard.
Ferrie misplaced a clearance to Mohamed Diomande after four minutes but the Gers midfielder's poor attempt at the unguarded goal from 20 yards missed the target, as did Ianis Hagi's long-distance effort minutes later.
Ferrie saved from Diomande, twice, winger Vaclav Cerny and attacker Bajrami and by the half-hour mark the home fans were beginning to run out of patience.
Just before the break Diomande managed to knock the ball wide of the target from eight yards following a corner and yet another chance was squandered.
Dessers and Nicolas Raskin replaced Bajrami and Rice for the start of the second half but it was Hamza Igamane who soon blasted high over the bar to end another Gers attack.
At the other end, Hurst was inches away from connecting with a cross from Ryan Duncan, who had been sent clear down the left by Zak Rudden.
Ridvan Yilmaz and John Souttar came on for Fernandes and Hagi after an hour, just before Ferrie pushed away a close-range header from Igamane following a Cerny corner.
Rangers were in a rut and struggling to get out.
Drozd had been on the pitch less than three minutes as a replacement for Hurst when he latched on to a corner from Louis Longridge, left Brazilian defender Jefte for dead and drove through the legs of Kelly from 12 yards before running to take the acclaim of the ecstatic travelling fans.
Rangers kept pushing but the visitors repelled everything thrown at them and by the end the home side were attacking with frustration rather than any guile, with Dessers failing with a chance in added time when he hesitated before having his shot saved by Ferrie.
Then came the penalty drama but even then Ferrie could not be beaten, diving to his left to push Tavernier's penalty away, and soon afterwards came the final whistle which confirmed a famous win.
Rangers' Philippe Clement when asked if he would consider his position:
"No, totally not. No, I don't expect this (talks with board) because you can put another manager in this game - would it be different in that sense?
"So what was yesterday? Progression was made, top eight in Europe and more consistency in the league and all these things, they don't change in 90 minutes.
"If you do that and make decisions in that way, then you make only decisions out of emotions and not out of what's been going on. So I don't expect this now.
"I understand that the fans are in emotions now. I know a lot of fans were on my side three hours ago. I know that.
"So now are the emotions of this game and I totally understand that because I'm also angry and frustrated about that, about this result and going out of the Cup because it was one of our big goals and our shortest chance to go to win a trophy this season.
"We all know that. That's probably also one of the reasons that the team was nervous in the second half, because they wanted that so much because they know how important it is for the club.
"Of course it's unacceptable, this result. Clearly, that's unacceptable. And we lost our composure, that's the main thing of today. We lost our cool in the second half to make the right decisions in the box.
"And we had a goalkeeper against who probably played the game of his life also. So you need to take that on the chin and it's a hard one to take.
"Again today we created enough to win three games. We didn't concede many chances. We get one shot on target (against us) and it's a goal.
"It's a hold-up today. It's a f****** frustrating one. Sorry to use that word. But it's my feeling for the moment. So I'm as frustrated as everybody else."
