After making his comeback for the U23s on Friday, after suffering a broken bone in his foot during the summer, the 17-year-old appeared as a second-half substitute.
Adam Lewis also netted a penalty for Steven Gerrard's side.
Reflecting on the outing, Gerrard told Liverpoolfc.com: "We were 2-0 down at half-time which basically summed up the story of the game for us.
"We were second best all over the park for 45 minutes and Leicester totally deserved their 2-0 lead.
"We only started playing in the second 45 minutes and I thought we just edged it, but we gave ourselves too much to do and to be fair to Leicester they managed the game well.
"Rhian [Brewster] made a huge difference when he came on for the last 30 minutes which I knew he would.
"We got it back to 3-2 but when we were chasing an equaliser we got done on a break for 4-2.
"Overall I've got no complaints with the result, but I have a lot of complaints with the lads not turning up for the first 45 minutes.
"If there is a big learning curve that comes out of this then that is when you play against quality opposition then we can't afford to turn up at half-time.
"This is the second time it has happened in pre-season, once against Fulham last weekend and now today, and we've been punished for it.
"I will never criticise a player if he misses chances or he gets a pass wrong, but we have to be critical of players and the U18s as a squad if we are second best in all areas of the pitch, because that is not acceptable."