Connor Goldson swept Rangers into an early lead but a late penalty in the first-half gave St Mirren a lifeline after a dominant display from the visitors.
The home side went ahead with Jamie McGrath’s second of the night shortly after the break and looked to be seeing out a memorable win before Steven Davis struck the equaliser after James Tavernier’s free-kick hit the post.
But there would be no extra-time as St Mirren rallied again and scored from close range in injury time to deny Steven Gerrard’s team a place in the semi-final.
Here’s how the players rated during the first defeat of the season for Rangers.
Scale - 10: One of the best performances you've seen. 9: Outstanding. 8: Very good. 7: Good. 6: Average. 5: Poor, 4: Very poor. 3: A terrible day at the office. 2: Abysmal. 1: One of the worst performances you've seen
5. Calvin Bassey - 5
Conceded the penalty and did not look like his usual self slotting in for Barisic at left back. Little sign of advances up the wing and clumsy for the penalty. Hooked shortly after half-time. Photo: Craig Williamson - SNS Group
6. Bongani Zungu - 7
Positionally excellent in the first half and always read two steps ahead of the play. Faded in second half and replaced but promising performance. Photo: Craig Foy - SNS Group
7. Joe Aribo - 5
Hung on to possession for too long and altogether quiet performance from the midfielder. Kept on for the full game to create but not much came off for him. Photo: Craig Williamson - SNS Group
8. Scott Arfield - 6
Got box-to-box and was allowed to by Zungu's positioning, but midfield didn't get enough of a grip and eventually replaced by late goal hero Davis Photo: Craig Williamson - SNS Group