Flynn was the fourth wicket to fall with the score at 229 in the 43rd over.
His dismissal brought Brad Wilson to the crease, who with Hickey put on a valuable partnership of 46 from 28 deliveries at a time when the innings looked unlikely to deliver on its earlier promise.
Powerful all-rounder Anurag Verma landed a couple of lusty blows off Jimmy Neesham before falling prey to some sharp work from Derek de Boorder, moving the score along to 292/6 with an over remaining.
Hickey played well again, adding an unbeaten 48 from 44 balls to get his side to 301/7 from their full complement, setting up what looked likely to be an enthralling chase.
Early wickets from Graeme Aldridge stifled that prospect before it had really begun, with openers Sam Wells and Aaron Redmond back in the hut with the score at 8/2.
Neil Broom and Neesham rebuilt the innings with a partnership of 86, but when both fell within the space of two overs the Volts were reduced to 103/4 in the 23rd over.
Contributions from Nathan McCullum (41) and de Boorder (31) gave the visitors a sniff, but they were always behind the eight ball on a pitch that suited the Knights' trio of spin bowlers.
Knights coach Grant Bradburn was pleased with the improved performance featuring subtle changes in bowling plans.
"It was a very good win, particularly with the way we played against Canterbury," said Bradburn. "To turn around a few things we knew we needed to improve was really satisfying."
Bradburn praised the roles Flynn, Devcich and relative newcomer Hickey played in the controlled display.