Northampton Town's youth team won 3-2 at AFC Wimbledon on Tuesday in the EFL Youth Alliance League Cup.
"We went down early, fought back from 1-0 down but showed great resilience to turn it around and win the game," said coach Jon Brady.
"We had a few spells where we were under the cosh but we dug out a result and got ourselves into the third round.
"The lads were brilliant and are excited to progress, it also keeps the unbeaten run since February intact so it's all positive at the moment and we look forward to the next game."
The Cobblers have a home tie against Peterborough United in the next round on a date tbc.