After falling behind to Dean Winnard’s strike early on, the Sky Blues hit back to secure a trip to either Cambridge United or Dover Athletic thanks to Marvin Sordell’s brace.
Elsewhere, Kyle Cameron entered the fray as a late substitute as Newport County finally got the better of Vanarama National League North side Alfreton Town.
Cameron came on in the 109th minute for the Exiles, who struck three extra time goals to bring the Derbyshire outfit’s gallant run to an end.
Meanwhile, Paul Woolston was named on the bench as Blyth Spartans lost 2-0 at Shaw Lane in the Doodson Sports Cup.