Colchester reached the third round of the Carabao Cup for the first time in 15 years after beating Premier League Crystal Palace on penalties.
A dull 0-0 draw was decided with a shoot-out and the Sky Bet League Two outfit scored all five of their spot-kicks, with Andros Townsend's miss proving costly as The U's won 5-4 to advance.
Palace, with Martin Kelly the only man to retain his place from Saturday's last-gasp win at Manchester United, had the better chances but struggled to break down a resolute Colchester side some 75 places below them in the football pyramid.
Victor Camarasa almost marked his Palace debut with an early opener but his driven effort from the edge of the box was pushed clear by Dean Gerken.
At the other end, Wayne Hennessey, making his first Palace appearance since being cleared by the Football Association of making a Nazi salute in April, did well to push away Ryan Clampin's angled strike.
Christian Benteke was the next to force a smart save out of Gerken and came even closer to a rare goal just after the half-hour as his fierce shot cannoned off the underside of the crossbar and bounced back into play.
The sides went in level at the break and only a fine stop from Gerken made sure it stayed that was soon after the interval as he spread wide to keep out a close-range attempt from Palace academy product Sam Woods.
That was the last clear-cut chance of a forgettable contest that was deservedly settled on penalties.
Townsend stepped up first but saw his penalty well-saved by Gerken, with Colchester then tucking away their first four attempts.
That left Zaha needing to score Palace's fifth to keep them in the tie and he did just that – only for 18-year-old Noah Chilvers to stroke home the decisive penalty.