OXFORD United's run in the Johnstone's Paint Trophy came to an end as they were knocked out on a penalty shoot-out by Southend United.
Alfie Potter was the unlucky player to see his spot kick saved by Daniel Bentley, who was brought on specifically for the penalties.
It completed a dramatic area semi-final, which lurched from one side to the other.
Goals from teenager Tyrone Marsh and Tom Craddock saw United come from behind to lead 2-1 at half time.
Southend scored twice in five minutes to snatch back the advantage after the break, but Sean Rigg's last-gasp header made it 3-3.
But unlike in the previous round, at Plymouth, the U's could not prevail from 12 yards and Southend will head through to the area final.
Marsh came in for the cup tied Justin Richards in one of three changes from the side which started Saturday's FA Cup defeat to Sheffield United.
Rigg and Michael Raynes were also promoted to the XI, at the expense of Peter Leven and Michael Duberry.
Southend boss Paul Sturrock named the strongest line-up available to him and the visitors struck the first blow after just six minutes.
Jake Wright conceded a free-kick, which Kevan Hurst swung in for Corr to head back across goalkeeper Ryan Clarke and into the net.
The U's responded well to the setback and drew level eight minutes later.
Alfie Potter turned Chris Barker inside out before picking out Rigg with his cross. The winger's diving header was kept out by goalkeeper Paul Smith, but Marsh pounced on the rebound to equalise for his first senior goal.
The hosts's line-up was unfamiliar, but the goal settled them down and Southend were second best for the remainder of the half.
Rigg enjoyed himself in a free role and he almost scored with a curling shot midway through the half which flew just wide.
The sparse home crowd did not have long to wait for the second goal, which arrived on 31 minutes.
It owed much to a fantastic 50-yard diagonal ball from Simon Heslop, which set Tom Craddock through in goal and he coolly lobbed Smith left-footed for his 12th goal of the season.
Southend were on the back foot, but were gifted a second goal after the break by Luke O'Brien.
The full back was caught in two minds by an aimless ball forward, but he ended up setting Sean Clohessy free to calmly beat Clarke.
Gavin Tomlin hit the crossbar with a header, but the striker quickly made amends by teeing up Corr to make it 3-2 with a fantastic finish into the top corner from 20 yards.
The U's had just over half an hour to conjure a second comeback of the night.
Craddock came close to a spectacular second goal, but he could only flick a shot over after a lung-busting run and cross from Rigg.
As a last resort defender Harry Worley was brought on to play as a makeshift striker.
His physical presence rattled Southend, who retreated and gave the U's a chance to press forward.
With a minute of the 90 remaining they were rewarded, as Rigg stooped to head in a Tony Capaldi corner.
But the euphoria was short-lived, as the Essex club held their nerve in the shoot-out to go through.