Pitted against a talented and dangerous Fulham side, the City youngsters had trailed up until the 80th minute after Archie Taylor had opened the scoring just before the break.
But the Blues kept pushing and creating chances and were rewarded with a three-goal salvo inside the final 10 minutes from substitutes Christian Dunbar-McDonald, Ryan McAidoo and Teddie Lamb.
City’s reward is a fourth-round tie at home to either Mansfield or Arsenal. And for Reiss a place in the next stage was no less than his players deserved.
“We stayed calm and tried not to force it. It can be easy, especially at youth level, to try to force things,” Reiss reflected.
“But we kept calm and kept our patience and that was what we wanted to see.
“We were quite good in the first half and had chances but then conceded out of a set play and then it was a tough game.
“We played against a good team who defended well in a lot of moments.
“But we kept going, we believed and created chances and, in the end, I think it was a deserved win.”
Play the video to watch Reiss’s reaction in full…