Elgin pulled off one of the best results in their history at Dens Park.
The Moray men were a goal down in 18 minutes when Cammy Kerr struck for Dundee.
But, buoyed by their first-half efforts, Elgin hit back to achieve a victory few would have thought likely with second-half goals by Rabin Omar and Shane Sutherland.
Omar’s inspiration, Calum Ferrie’s wild indiscretion and Sutherland’s intervention gave the Black and Whites and their 140 travelling fans a day out to remember.
What ought to have been a straightforward day out for Dundee ended with venom raining down from the stands, the 6-2 derby drubbing from the previous week rubbing salt into the wound.
Elgin have been a more entertaining prospect to watch in this season’s early throws than in recent memory. Their wins in the previous rounds of this competition were 4-3 and 5-4, against Hibernian Colts and Brechin City respectively, while their last league outing was a 3-3 draw with League 2 title contenders Edinburgh City.
After the derby debacle Dundee required little incentive for a palate-cleansing victory.
Kane Hemmings, preferred as Dundee’s lone striker, forced Tom McHale into an early save before Kerr gave the Championship side the lead.
Allowed to slalom inside by Omar, the right-back took aim from 25 yards with his weaker foot, an idea only he must have thought was a good one. Kerr was proved right as the ball dipped over McHale.
The expectation would have been for the Moray side to yield now that Dundee had the advantage.
But the Dark Blues were sloppy and cautious in some of their build-up play, giving some encouragement to a part-time side that have made the quarter-finals of this competition just twice in 19 years.
Matthew Cooper, ostensibly a right-back, being deployed in midfield, gave Elgin more protection defensively but the former Caley Thistle youngster was encouraged to get forward. He found himself on the end of a Kane Hester cross that Ferrie smartly tipped over.
If Elgin were going to perform some sort of heroic comeback, fortune was going to play a huge part. In 56 minutes Omar’s first-time shot from just inside the box could have gone anywhere. It flew into the top corner of the net.
Just two minutes later, Dundee’s Sean Mackie, making his first start since a loan move from Hibernian, majorly miscued his clearance and gave Elgin’s Hester a sniff. Keeper Calum Ferrie committed himself and lunged at the City striker wildly, pole-axing him and sending the ball breaking free.
Credit has to go to referee Grant Irvine, who allowed play to continue as Sutherland advanced on the ball and did what he does best, put it in the net.
Irvine went back and duly dismissed Ferrie, with the stopper trudging past the pocket of Elgin fans taking great joy in his sending-off. Youth team stopper Harrison Sharp, just 18, was now thrown into the fray.
Sutherland, outwith his goal, was excellent, relishing the tussle with former team-mate Josh Meekings and proving much-needed ballast for his side when they needed respite from their defensive duties.
It has to go down as Elgin’s greatest result under Gavin Price and one of their best in recent history.
A place in the fourth-round draw is now, proudly, theirs.
