Matt Tubbs held his nerve from the penalty spot as AFC Wimbledon reached the second round of the Johnstone's Paint Trophy with a shoot-out victory over Southend following a 2-2 draw at Kingsmeadow.
Substitute Tubbs scored the decisive kick to maintain a perfect record for the hosts in the shoot-out after Southend's Lee Barnard struck a post and Dons goalkeeper James Shea saved Ben Coker's spot-kick.
Wimbledon had twice pegged back their opponents with Kevin Sainte-Luce and then Adam Barrett's goal two minutes from time cancelling out a double from Jack Payne.
The visitors had taken the lead after five minutes when Myles Weston crossed for Payne to sweep home his first professional goal.
The hosts equalised after 16 minutes as Tom Beere's short corner allowed Sainte-Luce to strike a first-time shot past keeper Daniel Bentley. But the Dons were then reduced to 10 men when midfielder Harry Pell was shown a straight red card for a reckless high challenge on Dave Worrall.
Payne's 20-yard strike put Southend ahead after 51 minutes before left-back Barrett curled in a late effort to make it 2-2 after 90 minutes and force penalties, which brought a 4-2 success for the Dons.