The young Foxes headed into their second Group F fixture on the back of just one defeat in their last five fixtures, including last weekend's 3-2 win over Southampton in U18 Premier League South.
After 13 minutes at the Club's training ground, Sidnei Tavares located Tawanda Jethro Maswanhise to fire City into an early lead, which was curtailed by Seagulls defender Ed Turns on 23 minutes.
However, Leicester were swiftly back in front as midfielder Terell Pennant beat Southampton shot-stopper Roco Rees, before the visitors mounted an admirable comeback.
Just before the break, James Furlong was quickest out of the blocks to make it 2-2 while, in the 64th minute, Ben Wilson completed the turnaround to leave City in third place in Group F.
Following a 4-4 draw at Manchester United, the young Foxes currently have one point from their opening two matches, and next face West Bromwich Albion on Saturday 23 November (11am GMT kick-off).
The details...
City: Bosworth; Murch, Barrett, Sams, Flynn; Pennant, McAteer, Leathers, Tavares, Maswanhise (Loughlin 74'); Russ
Subs not used: Yseko, Obi, Marcal-Madivadua, Doherty
Goals: Maswanhise 13, Pennant 29'