Ben Harding scored the decisive penalty as Wycombe overcame Colchester in a Carling Cup thriller.
The hosts had gone into a two-goal lead following Scott Donnelly's 18-yard strike and a tap-in from Joel Grant.
The U's hit back with Kayode Odejayi's finish from Michael Rose's cross, and an Ian Henderson rocket from 25 yards.
A Steven Gillespie penalty in extra time for Colchester and a long-range equaliser from Stuart Beavon set the stage for Harding's decisive kick.
VIEWS FROM THE DRESSING ROOM
Colchester United manager John Ward told BBC Essex:
"I feel for my team, I think they've done everything possible to win the game.
"From being two goals down, we've handled it well, I've been delighted with the response of the team.
"For 30 minutes going up to half-time, I thought our football was absolutely excellent."
Wycombe manager Gary Waddock told BBC Three Counties Radio:
"The players are very pleased with progressing in to the next round, but they're also very pleased with their performance.
"Early on we lost our way in the first half when Colchester pegged us back but we got ourselves back in to the game in the second-half.
"We improved in that spell against a very good team, and you can tell [Colchester boss] John Ward has put a group of players together who are going to do very well this season."