MK Dons beat their bitter rivals AFC Wimbledon on penalties to progress to the second round of the EFL Cup.
Wimbledon took an early lead through Scott Wagstaff at Kingsmeadow, but the Dons responded with goals from Conor McGrandles and David Kasumu either side of half-time.
However, Luke O'Neill's last minute equaliser forced a penalty shootout which MK went on to win 4-2.
Both sides also missed penalties in normal time in a dramatic 90 minutes, while the animosity between the two clubs continued off the pitch with AFC choosing not to print a matchday programme, as is their right under new EFL guidelines.
The Dons will face Southend United in round two after a brace from 17-year-old Charlie Kelman helped the Shrimpers see off Stevenage, while Cambridge United pulled off a shock by beating Championship side Brentford on penalties courtesy of debutant Harvey Knibbs' winning spot-kick.
Luton Town also booked their place in the second round with a comfortable 3-1 victory over Ipswich Town at Kenilworth Road, and Colchester United were also convincing 3-0 winners over Swindon Town.
Northampton Town were on the verge of an upset when they took the lead at Swansea City through Matty Warburton's first professional goal, but the Swans fought back to eventually win 3-1.
Meanwhile, Peterborough United's poor start to the season continued with a second successive 1-0 defeat at Oxford United in the space of a few days.
Norwich City have been handed an away tie to League Two side Crawley Town after entering the competition at the second round stage.
EFL Cup second round draw
Crawley Town v Norwich City
Swansea City v Cambridge United
Cardiff City v Luton Town
Crystal Palace v Colchester United
Southend United v MK Dons