The Foxes bounced straight back from a late defeat to Reading in Premier League 2 last week to record their second successive PL Cup triumph and keep hopes alive of qualifying for the knockout stages of the competition.
Coach Ben Petty opted to make four changes to the XI, with Arlo Doherty, Mirsad Ali, Oliver Ewing and Kian Pennant all coming into the side for the clash at LCFC Training Ground.
After a goalless 90 minutes, it looked to be heading for a stalemate, until Briggs popped up with the all-important goal that sealed a precious 1-0 for the hosts.
It leaves Leicester third in Group G, on six points from five games. Behind Brentford on goals scored, the pair face off in their final group fixture on Friday 2 February - a 7pm kick-off in Seagrave.
Back to league action before then, Southampton are the visitors to LCFC Training Ground next Monday, in another 7pm kick-off.
The details...
City: Doherty; Cover, Wormleighton (c), Godsmark-Ford, Ali; Raikhy, Cartwright (Dyke 90+3'), Ewing (Grist 55'); Briggs, Pennant (Richards 65'), Thomas.
Unused subs: Young, Otchere.
Goal: Briggs 90+1'.
All times GMT.