Ademola Lookman and Kelechi Iheanacho have given Leicester boss Brendan Rodgers plenty of attacking options after grabbing the goals which sank Millwall in the Carabao Cup.
With Jamie Vardy given the night off, Lookman and Iheanacho took their chances with both hands in a 2-0 victory at The Den.
Winger Lookman, who grew up in nearby Peckham, marked his full Foxes debut with the opening goal shortly after half-time and Iheanacho wrapped up the victory with Leicester's second two minutes from time.
Assistant manager Chris Davies said: "Ade has been outstanding since he came in, with his training and mentality, that's been a real highlight, and he got his rewards today.
"It was a game of few chances so we had to work hard for the chances we got. It was great for Ade to get the goal.
"Kele scored an excellent goal, he set up the first one and then scored with a great strike. His all-round play was really good and it was a goalscoring performance, which is always good for a striker.
"We've got a really competitive squad so you're always trying to pick a balanced team, but the great thing about Kele is he's in great form.
"He was an important player for us last season and he will be an important player for us again this season."
Millwall, 18th in the Championship, had a decent opportunity to open the scoring before half-time but Ben Thompson's header looped onto the roof of the net.
And four minutes into the second half Leicester's pressing paid off when Kiernan Dewsbury-Hall won possession just inside the Millwall half.
Iheanacho smuggled the ball away and when his shot was saved by Lions keeper George Long, former Charlton youngster Lookman arrived to slam home the rebound.
Millwall came closest to an equaliser when Connor Mahoney bent a free-kick into the area which substitute Benik Afobe was inches away from touching into the net.
But with time running out Iheanacho finished a swift Foxes counter-attack with a stinging shot into the roof of the net to seal their passage into round four.
Lions boss Gary Rowett, a former Leicester player, was unhappy with the first goal.
He said: "When you look at a game like that, when you go toe to toe with a very good Premier League side, you can't make mistakes.
"We gave the ball away and allowed them into a scoring position and they are sometimes the moments that cost you. But I thought we competed really well tonight."
