Leicester led 2-0 through Shinji Okazaki but had Marcin Wasilewski sent off before a Cesc Fabregas double saw Chelsea through in extra time.
An extra-time brace from Cesc Fabregas completed a thrilling 4-2 comeback win for Chelsea at 10-man Leicester City in the EFL Cup third round.
Chelsea's defence was highly culpable as Shinji Okazaki ended a 13-game goal drought with two first-half goals for the Premier League champions, but two of Antonio Conte's back four were able to make amends either side of the interval.
Captain Gary Cahill headed home a Fabregas corner in first-half stoppage time before Cesar Azpilicueta – who tried in vain to hack both Okazaki goals off the line – elevated a pulsating match further with a spectacular long-range volley in the 49th minute.