Chelsea recovered from a dreadful start to defeat Leicester 4-2 after extra time at the King Power Stadium.
Shinji Okazaki netted a brace in the opening 34 minutes as Chelsea’s defending once more came under scrutiny.
The Blues were seemingly meandering towards half-time when Gary Cahill was given a free header from a corner to reduce their arrears.
That proved the turning point as Cesar Azpilicueta’s stunning volley on 49 minutes levelled the game.
Chelsea looked more likely to win thereafter but they were thwarted by the home side repeatedly. A second booking for Marcin Wasilewski meant Leicester were up against it in extra time and Cesc Fabregas scored a quick-fire double to earn Chelsea the win.
Some ponderous defending from Cahill and Azpilicueta, along with stand-in goalkeeper Asmir Begovic, allowed Okazaki to head the ball goalwards on 17 minutes from an angle, the ball just about sneaking over the line to give Leicester the first blow.
The same player benefited again on 34 minutes, when Pedro’s clearance went straight to Andy King.
The midfielder poked a clever pass into Okazaki’s path and his scuffed finish once more had just enough to get over the line and make it 2-0.
Leicester would have been relishing that lead at the break but in stoppage time Cahill had time and space to head the Blues back into the contest.
With one defender making amends there, Azpilicueta got in on the act in stunning fashion four minutes into the second half. His thunderous right-foot volley from 20-yards flew into the net past Robert Zieler.
Diego Costa and Jamie Vardy were introduced as both teams sought to avoid an extra 30 minutes.
Costa came close on numerous occasions and really should have won the game within moments of coming on but he shot wide from inside the box. At the other end another sub, Leonardo Ulloa, glanced a header on for King but he couldn’t keep the ball down at the back post.
With extra time looming, Wasilewski made silly foul on Costa and duly received a second yellow card to put Leicester’s backs against the wall.
Within four minutes of the restart, the game was won.
Fabregas was on the end of a flowing Chelsea move to wrong foot Zieler from inside the box on 92 minutes and just two minutes later the same player blasted home from close range to seal victory for Chelsea on another mixed evening for Antonio Conte’s outfit.