Colchester boss John Ward hailed Bradford for their part in the 4-3 thrilling FA Cup clash.
Andrew Bond, David Mooney(2) and Brian Wilson won it for the Us.
Ward said: "Bradford made it hard work and I think that's great credit to them.
"They're a team in form and they have a lot of experience and an excellent manager, with Wayne Jacobs working with them.
"It was a tough game and it was as tough a game as we've had.
"`We're delighted to win it and go and that's what the FA Cup is all about."