Pep Guardiola savoured one of Manchester City's most satisfying wins of the season as he ordered his players to celebrate again.
The runaway unbeaten Premier League leaders have been steamrolling opponents this term to amass an 11- point lead.
Here Guardiola's side, with nine changes, needed a tense penalty-shootout to progress to the last four of the Carabao Cup.
It was perhaps not as impressive as their recent derby win at Manchester United which sparked complaints from Jose Mourinho about the visitors' celebrations.
They were made to sweat after Jamie Vardy's injury-time penalty from a disputed spot-kick took the tie to extra-time by cancelling out Berhando Silva's opener.
But City still ended up progressing as Vardy hit the post with a spot-kick in the shoot-out and Riyad Mahrez was denied by keeper Claudio Bravo.
Guardiola beamed: “I think it is a good sign for the club and that is why I am so happy.
“What is important is how we react, so what if it is a penalty or not a penalty?
“It was the last minute so it was tough, especially with a lot of young players.
“Big teams you have to handle the bad moments and have to find situations.
“I said in the locker room to celebrate again.
“You have to wait to win the title and even in the position we are in you don't know if we are able to win the Premier League.
“But in the process in the moment you have to celebrate always. We will enjoy it.”
The visitors should have led by more than 1-0 at the break following Silva's 26th-minute opener.
Silva blew two good chances before finally breaking the deadlock.
He eventually scored after Kelechi Iheanacho was guilty of losing the ball near the halfway line after Ilkay Gundogan robbed him.
The Nigerian striker appealed in vain for a foul and didn't play to the whistle, leaving Gundogan to rampage forward with purpose.
His run to the top of the box ended with a deft right-foot flick with the outside of his foot to the unmarked Silva.
He made no mistake this time to toe-poke in a low left-foot shot under Ben Hamer.
But City weren't at their clinical best without the likes of Sergio Aguero, Kevin De Bruyne and Raheem Sterling.
Leicester boss Claude Puel surprisingly left his key men on the bench too with seven changes of his own.
The introduction of both Vardy and Mahrez off the bench in the 56th minute changed the contest and sparked the hosts into life.
Leicester, buoyed by fans' positive reaction, went more direct with Demarai Gray a big threat too once he came on.
Gray even beat City sub Kyle Walker in a race into the box in stoppage time.
He then went sprawling under a disputed challenge from Walker and referee Bobby Madley infuriated the visitors by pointing to the spot.
Vardy stepped up to keep his nerve to thump in his eighth of the season low into the bottom corner with his right-foot.
It left unhappy Guardiola mocking Gray for diving as he mimicked a tumble at the end of 90 minutes.
But the Spaniard was smiling by the end as Gundogan, Yaya Toure, Lukas Nmecha, Gabriel Jesus, all scored from the spot.
Guardiola even laughed off a pitch invader slipping over trying to get close to him to hurl abuse before being escorted off 10 minutes from the end of normal time.
The Spaniard added: “He wanted my shirt. Next time he has to change his shoes. I felt safe.”
Foxes boss Puel, whose side lost 3-0 at home to Crystal Palace previously, insisted: “I don't regret the changes.
“We were unlucky. We have had most chances. It was important to give a good response after the last league game. I like our positive outlook."
PLAYER RATINGS
Leicester: Hamer 6, Amartey 6, Dragovic 6 (Benalouane 110, 6), Maguire 7 booked, Fuchs 7, Albrighton 6 (Mahrez 56, 7), King 6, Iborra 7, Chilwell 6 (Gray 71, 7), Okazaki 6, Iheanacho 6 booked ( Vardy 56, 7 )
Man City: Bravo 8, Danilo 7 booked, Adarabioyo 7, Mangala 7 (Walker 81, 6 booked), Zinchenko 7, B Silva 7, Toure 7, MOTM Gundogan 8 booked, Diaz 6 (Nmecha 88, 7), Foden 7 (Dele-Bashiru 90, 6), Jesus 7.
Referee: Robert Madley