Mark Beck and David Symington scored as League One side Carlisle defeated Championship visitors Ipswich in the second round of the Capital One Cup.
Teenage substitute Beck headed in a 90th-minute equaliser to cancel out Massimo Luongo's first-half opener in dramatic fashion at Brunton Park.
And Symington, another of Carlisle boss Greg Abbott's substitutions, lashed in a 99th-minute winner to cause an upset.
It capped a bad week for Town, who were thumped 6-0 by Blackpool on Saturday.
Paul Jewell's men kept the Carlisle defence busy in the opening 45 minutes.
Home keeper Adam Collin twice kept the home side in the game with last-ditch saves, using his legs to thwart Josh Carson from close range before denying Michael Chopra in a one on one.
But Collin had no chance in preventing a rasping shot from teenage midfielder Luongo, who signed on a season-long loan from Tottenham last month, fizzing past him into the net.
The Tractor Boys faded in the second half and Carlisle capitalised as 18-year-old duo Beck and Symington scored to send the Cumbrian crowd into raptures.
Carlisle boss Greg Abbott: "Symington has no fear and you expect the unexpected with him. But he will learn to get more consistent and he's shown that he can come on and make an impact.
"Beck made a significant contribution and David was a real handful with his power and pace and he has unbelievable shooting power.
"With our guts and determination we probably deserved to come out winners. Sometimes the fans have got to be a bit patient. As these youngsters get older they will get more consistency."
Ipswich manager Paul Jewell: "We didn't pass the ball well enough in the second half and this result shows our frailties. We need more power and bite in the team.
"We controlled the first half but missed chances which could have put the game behind us. We were not ruthless enough all over the pitch.
"We have to do the things that good teams do which is scrap and fight."