The visitors had their backs against the wall for large spells against Brendan Rodgers' men, but in the end, Ross Barkley's second-half effort sent the top-four contenders into the final four of the competition.
Whenever they slow the pace down and show no fear of running in behind the defence, Chelsea always seem to find more success. They made sure to mix it up by attacking down both flanks, and at the opposite end, you can see how much trust they put in Willy Caballero to guide the team in difficult cup ties such as this.
Leicester's attacking frailties saved Chelsea on more than one occasion as the Blues were simply unable to plug the holes they had at the back. At times in the first half they were trying to play quick, attractive football, but the final pass was always lacking. Whenever Plan A didn't work, it was clear to see that there wasn't much of a backup plan until late in the game.
Manager rating out of 10
7 -- The decision from Frank Lampard to start with a 4-2-3-1, allowing N'Golo Kante and Billy Gilmour to work alongside each other, was a strange one. The first half showcased their inability to really grab hold of a big game like this in that formation, but to his credit, the former midfielder made three strong changes at the interval and pushed his side to take control and push the tempo in the second half.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Willy Caballero, 7 -- The cup specialist continues to shine when it matters after another confident display, with his best moment coming in the form of a nice low save to his left in the 20th minute.
DF Emerson Palmieri, 5 -- The full-back constantly relies on cover from elsewhere to get himself out of danger, with the best possible word to describe his performance today being "lazy".
DF Kurt Zouma, 5 -- There's always a heart attack or two in store for Chelsea fans when Zouma is on the pitch, and the same was true at the King Power after a showing that lacked leadership and composure.
DF Antonio Rudiger, 5 -- His clumsy, unpredictable nature could easily have cost his side a place in the semifinals after a few moments of real sloppiness.
DF Reece James, 6 -- While he's capable of muscling attacking players off of the ball, it says something that James' highlight was a silly 13th-minute foul before being pulled off at half-time.
MF N'Golo Kante, 6 -- After a shaky first-half display, the former Leicester star found more of a rhythm in the second 45, but still struggled to contain Wilfred Ndidi throughout.
MF Billy Gilmour, 4 -- There was a real learning curve in store for the youngster this afternoon, as he was subbed off at half-time after giving the ball away several times.
MF Willian, 7 -- The Brazilian ran at Leicester with real authority when he was given the chance to do so, and while he wasn't always on the mark, he provided a great assist for Barkley's goal.
MF Mason Mount, 5 -- Aside from a decent pass inside to Pulisic in the 30th minute, it was a quiet day at the office for a seemingly unmotivated Mount
MF Christian Pulisic, 8 -- It was a Man of the Match outing for the American as he drove the heart of Chelsea's attack until being subbed off, with everything from his turns to his vision on point.
FW Tammy Abraham, 5 -- The popular forward was more urgent in the second half but couldn't avoid being marked out of the game. He's a world-class finisher, but he needs to time his runs better.
MF Mateo Kovacic, 8 -- One of the Premier League's classiest players struck again with intricate passing, wonderful anticipation on and off the ball and a real box-to-box attitude.
MF Ross Barkley, 7 -- The England international's determination proved to be the difference-maker, with his 63rd-minute strike winning the tie for the Blues.
MF Ruben Loftus-Cheek, N/R -- Was thrown onto the left wing in a move that will have baffled supporters, but didn't serve as too much of a detriment to the team's flow.
MF Pedro, N/R -- Helped to carry the ball forward late in the game, but didn't do enough to make a substantial impact.