Colchester yth 3 - 2 Cardiff City AET
City had taken a first half lead from Jamal Easter, Colchester scored two in a minte in the second half and looked to have won the tie but Ryan Morgan scored in the 89th minute to force another 30 mins.
United got the winner and they progress into round 5 to face Crewe.
Unlucky lads. It's back to academy action this weekend with a trip to MK Dons tomorrow.