AFC Wimbledon boss Neal Ardley hailed his side’s character after a night of Johnstone’s Paint Trophy drama at the Cherry Red Records stadium.
After 90 minutes could not separate 10-man Dons and Southend at 2-2, it was Matt Tubbs who dispatched the winning spot-kick and give Dons their first major cup win of any kind since November 2012.
Southend took an early lead through Jack Payne before Dons levelled through Kevin Sainte-Luce off the back of a well-rehearsed corner routine.
Moments later Dons were put on the back foot when Harry Pell, making his first start of the season, was shown a straight red for a high challenge on Dave Worrell.
After the break, Payne restored Southend’s lead and it looked like being enough until Dons defender Adam Barrett unleashed a 25-yard curler past Dan Bentley in the dying moments to take the tie to the ultimately successful penalty shoot out.
Ardley said: “After what’s happened in the last few home games and then to go 1-0 down, to come back I thought the character was excellent.
“We’ve asked the boys to be brave and try things we work on in training, and the first goal was one of those, which is really pleasing.
“Last weekend [against Stevenage], I possibly went for the game too earlier, but against Southend I made sure we stayed in the game, we dug in, and it took everyone to do that.”
He added: “It was a red card, absolutely. I want to work on the positives, but Harry’s had too many bookings and he has not been on the pitch that long.”
Dons return to League Two action this weekend at Carlisle, who sacked their manager Graham Kavanagh on Monday.