Redbridge then regained the lead on their next attack after NLR again failed to clear their lines.
The second half was all Raiders but Redbridge stood firm most spectacularly when their keeper pulled off a superb penalty save from Green after Gilbert was fouled in the box.
With 90 minutes on the clock and Raiders pressing for an equaliser, Redbridge had a 3-on-1 break, but a superhuman effort from Rob Blackman saw him make a vital interception after a 60-yard sprint back to cover.
With only seconds to go Josh Goldstein was then upended 25 yards out and it was Goldstein who stepped up to send a sublime free kick into the back of the net to equalise.
Extra-time was all Raiders and the decisive goals duly came in the second period with Gilbert climbing high to nod home a great far post header from a long Anthony Goodmaker diagonal ball, and then Gilbert turned provider outfoxing his marker before pulling the ball back to Waissel who thumped home the fourth.
Relieved NLR joint-manager Jonny Adelman told JC Sport: "It was a very very satisfying win, and a gutsy never say die effort from the boys."
